Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 03 May 2021 22:52:13 Jon Elson wrote:

> On 05/03/2021 07:35 PM, Gene Heskett wrote:
> > Thanks Jon, I hadn't thought of it in that exact manner, and it
> > makes perfect sense.  So I'll likely give it a shot in the next few
> > days.
> >
> > Does there seem to be a golden ratio that works well consistently?
>
> Some people seem to have a feel for the math involved and
> can come up with approximations.
> I do it by feel and sound, with a lot of Halscope traces.
>
> Jon
>
I guess we're in the same try it and see campsite then, Jon.

Although hooking my new scope up to the pwmgen's output going to the BTS 
7960 board was nice and educational.  Its 10" screen can be seen and 
read easily from several feet away. 350 megahertz bandwidth, 4 color 
trace sampler. Siglint's best.  Sure made it easy to see what the pwmgen 
was doing. And thinking outside the box a bit, I tapped into hal and 
sent some of it to spare i/o, also much faster than the halscope but 
broken by the servo thread time quantization. Too bad the 5i25/7i76 
doesn't have more analog outputs though. Being able to export the analog 
following error to a huge display sure would be nice. you could see it 
in real time without all the bs of having to switch focus with the mouse 
to exersize it, that is a certified PITA that leads to lots of mistakes 
because the nouse focus has to be shifted so many times to do it. 
Your "go" click winds up destroying you halscope setup, so you have to 
wait for the thing to finish, set it up again to look at what you 
intended to see, then remember that you must waste a click to get the go 
focus back to the mdi line and away from the halscope. 

Now if linux had a focus follows mouse that actually worked.. But 
I've not found that particular magic twanger yet. You could do it 15 
years ago, why not now?

Thanks Jon.

Cheers, Gene Heskett
-- 
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Re: [Emc-users] Maybe a minimally printed harmonic drive? -> tuning manually -> agree with mathematics

[Nicklas SB Karlsson]

Den 2021-05-04 kl. 01:22, skrev Jon Elson:

On 05/03/2021 12:03 PM, Nicklas SB Karlsson wrote:

Den 2021-05-03 kl. 17:42, skrev Jon Elson:

Assuming machine is lubricated there shear force in oil/grease depend 
on speed so it might actually be rather close to viscous friction and 
hence rather close to linear. Then an oil/grease pump is used for 
lubrication there will be a thin oil film even at slow speed and 
standstill otherwise stick-slip effect might happen.


In doubt FF2 make any big difference anyway unless you are able to 
hit accurate with FF1.



There are many "frictions" in the system.  Shafts and bearings, 
possibly belts and pulleys, leadscrews and of course the linear slide 
itself.  I'm lumping them all together.


My current tuning scheme is set P low enough so the machine moves, but 
with lots of following error.  Set I and D to zero, and FF0 also, or 
possibly a little D if required.  Then, adjust FF1 very carefully, 
until the error on various velocity jogs is nearly zero. Some systems 
have a nonlinearity in the amps, so you have to compromise for minimal 
following error at a median speed.  Others are quite linear, and one 
FF1 value gives very small error over a wide range of speed.

Agree with my mathematics.
Then, add just a TINY bit of FF2 to reduce the accel/decel spikes. 
Then, find the highest P that you can without oscillation, add a 
little D and that about does it.


TINY bit of FF2 agree with my mathematics. My mathematics say you need I 
to get accurate following. I found manually tuning usually work rather well.


Mathematical modeling and analysis is more useful for slow systems, 
instability happen also to slow systems, oscillations may take minutes. 
In serial produced product it make sense with more thorough analysis to 
make sure marginals are good.




This tuning scheme works pretty well with analog velocity servos and 
my PWM system, where the motor's back EMF works a lot like velocity 
feedback.


My mathematics say if you feed motor with a voltage in sort of motor's 
back EMF work like a velocity feedback so voltage control speed. My 
mathematics also say FF1 compensate for the motor's back EMF or velocity 
if servo drive have velocity as input signal. So I would say there is 
agreement also here in sort of.



Nicklas Karlsson



Jon


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Jon Elson]

On 05/03/2021 07:35 PM, Gene Heskett wrote:


Thanks Jon, I hadn't thought of it in that exact manner, and it makes
perfect sense.  So I'll likely give it a shot in the next few days.

Does there seem to be a golden ratio that works well consistently?


Some people seem to have a feel for the math involved and 
can come up with approximations.

I do it by feel and sound, with a lot of Halscope traces.

Jon


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 03 May 2021 19:25:48 Jon Elson wrote:

> On 05/03/2021 02:34 PM, Gene Heskett wrote:
> > Friction will of coarse vary, but assume the amplitude of
> > the jitter is constantly reset to zero by a passing edge
> > from the encoder, but it times out in 2 millisecs. Leaving
> > the pwmgen outputing a very low duration pulse in one
> > direction or the other because the combo of friction and a
> > d term combines to coast it to a friction stop, some 30
> > arc-seconds from where the gcode sent it. Now, because the
> > jitter control has timed out, a counter watching each
> > direction pulse is free to increment its count. That
> > counter is added to the control signal in the direction to
> > reduce the error. And its incremented by the pulse from
> > that pwgmen's dir+ or dir- output. And in a few
> > milliseconds the motor will move enough to output an
> > encoder edge. That resets the counters, and the motor will
> > not have enough to keep moving. But the pwmgen isn't
> > satisfied yet so it keeps on outputting a 1% duty pulse on
> > one or the other of its dir signals, Wash, rinse repeat,
> > the motor is constantly being tickled enough by a 1 count
> > move in the wanted direction until the pwmgen sees a match
> > and stops tickling the motor.
>
> Well, this is sort of what the I and D are supposed to
> accomplish. I creeps up the command to make it move toward
> the null point, but D backs it off as soon as it moves past
> an encoder edge.
>
Thanks Jon, I hadn't thought of it in that exact manner, and it makes 
perfect sense.  So I'll likely give it a shot in the next few days.

Does there seem to be a golden ratio that works well consistently?

Take care and stay well.

> Jon

Cheers, Gene Heskett
-- 
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 soap, ballot, jury, and ammo. Please use in that order."
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If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Jon Elson]

On 05/03/2021 02:34 PM, Gene Heskett wrote:
Friction will of coarse vary, but assume the amplitude of 
the jitter is constantly reset to zero by a passing edge 
from the encoder, but it times out in 2 millisecs. Leaving 
the pwmgen outputing a very low duration pulse in one 
direction or the other because the combo of friction and a 
d term combines to coast it to a friction stop, some 30 
arc-seconds from where the gcode sent it. Now, because the 
jitter control has timed out, a counter watching each 
direction pulse is free to increment its count. That 
counter is added to the control signal in the direction to 
reduce the error. And its incremented by the pulse from 
that pwgmen's dir+ or dir- output. And in a few 
milliseconds the motor will move enough to output an 
encoder edge. That resets the counters, and the motor will 
not have enough to keep moving. But the pwmgen isn't 
satisfied yet so it keeps on outputting a 1% duty pulse on 
one or the other of its dir signals, Wash, rinse repeat, 
the motor is constantly being tickled enough by a 1 count 
move in the wanted direction until the pwmgen sees a match 
and stops tickling the motor.


Well, this is sort of what the I and D are supposed to 
accomplish. I creeps up the command to make it move toward 
the null point, but D backs it off as soon as it moves past 
an encoder edge.


Jon


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Jon Elson]

On 05/03/2021 12:03 PM, Nicklas SB Karlsson wrote:

Den 2021-05-03 kl. 17:42, skrev Jon Elson:

Assuming machine is lubricated there shear force in 
oil/grease depend on speed so it might actually be rather 
close to viscous friction and hence rather close to 
linear. Then an oil/grease pump is used for lubrication 
there will be a thin oil film even at slow speed and 
standstill otherwise stick-slip effect might happen.


In doubt FF2 make any big difference anyway unless you are 
able to hit accurate with FF1.



There are many "frictions" in the system.  Shafts and 
bearings, possibly belts and pulleys, leadscrews and of 
course the linear slide itself.  I'm lumping them all together.


My current tuning scheme is set P low enough so the machine 
moves, but with lots of following error.  Set I and D to 
zero, and FF0 also, or possibly a little D if required.  
Then, adjust FF1 very carefully, until the error on various 
velocity jogs is nearly zero. Some systems have a 
nonlinearity in the amps, so you have to compromise for 
minimal following error at a median speed.  Others are quite 
linear, and one FF1 value gives very small error over a wide 
range of speed.
Then, add just a TINY bit of FF2 to reduce the accel/decel 
spikes. Then, find the highest P that you can without 
oscillation, add a little D and that about does it.


This tuning scheme works pretty well with analog velocity 
servos and my PWM system, where the motor's back EMF works a 
lot like velocity feedback.


Jon


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 03 May 2021 11:42:54 Jon Elson wrote:

> On 05/03/2021 02:57 AM, Gene Heskett wrote:
> > More specifically, which of the F's is suitable for forcing a closer
> > to null settling point when there is considerable friction in the
> > system?
>
> That's the problem!  Friction is nonlinear, and it hurts
> during acceleration but HELPS during deceleration.  So, a
> single FF2 setting can never be optimal.  You have to use a
> compromise value.
>
Or, my middle of the night idea about some jitter in the control signal. 
Derived by something like this outline.

Friction will of coarse vary, but assume the amplitude of the jitter is 
constantly reset to zero by a passing edge from the encoder, but it 
times out in 2 millisecs. Leaving the pwmgen outputing a very low 
duration pulse in one direction or the other because the combo of 
friction and a d term combines to coast it to a friction stop, some 30 
arc-seconds from where the gcode sent it.  Now, because the jitter 
control has timed out, a counter watching each direction pulse is free 
to increment its count. That counter is added to the control signal in 
the direction to reduce the error. And its incremented by the pulse from 
that pwgmen's dir+ or dir- output. And in a few milliseconds the motor 
will move enough to output an encoder edge. That resets the counters, 
and the motor will not have enough to keep moving.

But the pwmgen isn't satisfied yet so it keeps on outputting a 1% duty 
pulse on one or the other of its dir signals, Wash, rinse repeat, the 
motor is constantly being tickled enough by a 1 count move in the wanted 
direction until the pwmgen sees a match and stops tickling the motor.

> > Something that will see it sitting at 3% power constantly, and will
> > raise the gain enough to move it another arc-second for a more
> > perfect null.
>
> The FF's will never be of value there.

Debateable, FF1 is someplace in the 20's to get a cruising error null.

> This is what the I 
> term is SUPPOSED to help with, but I
> have not found it to really accomplish much.

I use it, but determining the value is a puzzle,
Here is whats working fairly accurate, and stable for that BS-1 clone.

#
# Axis A
#
[AXIS_A]
MAX_VELOCITY= 30.000
MAX_ACCELERATION= 1500.00

[JOINT_3]
TYPE= ANGULAR
HOME= 0.0
HOME_SEQUENCE   = 3
HOME_SEARCH_VEL = 9.0
HOME_LATCH_VEL  = -1.0
HOME_FINAL_VEL  = 30
HOME_OFFSET = 4.498500
VOLATILE_HOME   = 1
FERROR  = 0.50
MIN_FERROR  = 0.25
MAX_VELOCITY= 30.000
MAX_ACCELERATION= 1500.00
P   = 6000
I   = 0.500
D   = 0.500
FF0 = 0
FF1 = 21.5
FF2 = 0.55
BIAS= 0
DEADBAND= 0.00015
BACKLASH= .1
MAX_OUTPUT  = 900.
SERVO_SCALE = 666.7
PWMGEN_TYPE = 2

Thr MAX_VELOCITY is restricted to keep it from overshooting and reversing 
the motor to come back, but at the higher speeds, that controller, a 
dual BTS-7960 tries to reverse it at speed, crowbaring a 450 watt 24 
volt supply, which needs about 3 minutes to cool and recover. I can go 
to at least 25,000 for Pgain before it starts to oscillate but its 
noticeably less stable above 15,000.

> That may have 
> more to do with the servo characteristics of my machines,
> though.

Each system seems to write its own rules.

> Jon

Take care and stay well Jon.

>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Nicklas SB Karlsson]

Den 2021-05-03 kl. 17:42, skrev Jon Elson:

On 05/03/2021 02:57 AM, Gene Heskett wrote:


More specifically, which of the F's is suitable for forcing a closer to
null settling point when there is considerable friction in the system?
That's the problem!  Friction is nonlinear, and it hurts during 
acceleration but HELPS during deceleration.  So, a single FF2 setting 
can never be optimal.  You have to use a compromise value.


Assuming machine is lubricated there shear force in oil/grease depend on 
speed so it might actually be rather close to viscous friction and hence 
rather close to linear. Then an oil/grease pump is used for lubrication 
there will be a thin oil film even at slow speed and standstill 
otherwise stick-slip effect might happen.


In doubt FF2 make any big difference anyway unless you are able to hit 
accurate with FF1.



Nicklas Karlsson



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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Jon Elson]

On 05/03/2021 02:57 AM, Gene Heskett wrote:


More specifically, which of the F's is suitable for forcing a closer to
null settling point when there is considerable friction in the system?
That's the problem!  Friction is nonlinear, and it hurts 
during acceleration but HELPS during deceleration.  So, a 
single FF2 setting can never be optimal.  You have to use a 
compromise value.
  
Something that will see it sitting at 3% power constantly, and will

raise the gain enough to move it another arc-second for a more perfect
null.
The FF's will never be of value there.  This is what the I 
term is SUPPOSED to help with, but I
have not found it to really accomplish much.  That may have 
more to do with the servo characteristics of my machines, 
though.


Jon


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Sunday 02 May 2021 21:02:29 Gene Heskett wrote:

> On Sunday 02 May 2021 16:34:43 Jon Elson wrote:
> > On 05/02/2021 01:00 PM, Chris Albertson wrote:
> > > The below is exactly true.  The problem is that PID is widely used
> > > and PID is only "reactive" it can only deal with what has already
> > > happened and the time lag is the source of oscillations.In the
> > > past, PID was the only control option because we had limited
> > > computing power.
> >
> > True for classic PID.  The PID calculation in LinuxCNC also
> > has feedforwards (FF0 - FF2) which
> > are quite useful, as they give an approximation of the
> > required drive to the motor without the output, move, sample
> > delay.
>
> Yes, and that I have found usefull.  But using them intelligently
> isn't at all well explained by the docs we have. Time constants and
> their effects are are not at all well explained. The bottom line is
> that if and when you hit the magic settings, you still have no idea
> why this works and that doesn't.
>
More specifically, which of the F's is suitable for forcing a closer to 
null settling point when there is considerable friction in the system? 
Something that will see it sitting at 3% power constantly, and will 
raise the gain enough to move it another arc-second for a more perfect 
null. Best applied where a pwmgen is operating in mode 2 to drive an H 
bridge. I've considered adding a high frequency jitter to the control so 
that friction might be overcome, but that needs to be controlable, 
something that as long as the error exists, will raise the amplitude of 
the jitter until it does move. Something that looks at the encoder to 
detect movement that should reset the accumulated jitter amplitude to 
start a new cycle when the encoder says it has moved for instance.

See what happens when I let my imagination out to play at 4 am without a 
chaperone?

> > Jon
> >
> >
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> Cheers, Gene Heskett


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Sunday 02 May 2021 16:34:43 Jon Elson wrote:

> On 05/02/2021 01:00 PM, Chris Albertson wrote:
> > The below is exactly true.  The problem is that PID is widely used
> > and PID is only "reactive" it can only deal with what has already
> > happened and the time lag is the source of oscillations.In the
> > past, PID was the only control option because we had limited
> > computing power.
>
> True for classic PID.  The PID calculation in LinuxCNC also
> has feedforwards (FF0 - FF2) which
> are quite useful, as they give an approximation of the
> required drive to the motor without the output, move, sample
> delay.
>
Yes, and that I have found usefull.  But using them intelligently isn't 
at all well explained by the docs we have. Time constants and their 
effects are are not at all well explained. The bottom line is that if 
and when you hit the magic settings, you still have no idea why this 
works and that doesn't.
> Jon
>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Eric Keller]

A well-tuned PID with feedforward is capable of controlling a machine tool
without any issues.  Sure there are better ways to implement a control, but
the results are not going to be significantly different on something as
simple as a machine tool.  After the academic controls community played
around with robust control for 15 years, it's really difficult to get
funding to do any more work in that field. I'm not sure what it would take
to revive it.
Eric Keller
Boalsburg, Pennsylvania


On Sun, May 2, 2021 at 4:38 PM Jon Elson  wrote:

> On 05/02/2021 01:00 PM, Chris Albertson wrote:
> > The below is exactly true.  The problem is that PID is widely used and
> PID
> > is only "reactive" it can only deal with what has already happened and
> the
> > time lag is the source of oscillations.In the past, PID was the only
> > control option because we had limited computing power.
> True for classic PID.  The PID calculation in LinuxCNC also
> has feedforwards (FF0 - FF2) which
> are quite useful, as they give an approximation of the
> required drive to the motor without the output, move, sample
> delay.
>
> Jon
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Jon Elson]

On 05/02/2021 01:00 PM, Chris Albertson wrote:

The below is exactly true.  The problem is that PID is widely used and PID
is only "reactive" it can only deal with what has already happened and the
time lag is the source of oscillations.In the past, PID was the only
control option because we had limited computing power.
True for classic PID.  The PID calculation in LinuxCNC also 
has feedforwards (FF0 - FF2) which
are quite useful, as they give an approximation of the 
required drive to the motor without the output, move, sample 
delay.


Jon


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Re: [Emc-users] Maybe a minimally printed harmonic drive? --> MPC and other control theory

[Nicklas SB Karlsson]

Den 2021-05-02 kl. 20:00, skrev Chris Albertson:

The below is exactly true.  The problem is that PID is widely used and PID
is only "reactive" it can only deal with what has already happened and the
time lag is the source of oscillations.In the past, PID was the only
control option because we had limited computing power.   People are
starting to use MPC for motion control now.  MPC is predictive and can
account for "spring back", backlash and the time it will take to
decelerate.   But it does require modern compute power.   If you google,
you find many papers on MPC applied to milling machines starting in about
2010.


So what's the difference between MPC Model Predictive Control and feed 
forward? Solve equation analytical instead of using analytical solution?


Read some about it but did not figure out what they are doing but should 
not be able to predict something not in the model.



Eventually, this will filter down to the open-source DIY hobby community.
If you have ever seen a machine running with this kind of controller it is
visible even just looking at it by eye, the machine looks "alive" and moves
more like a human or a dog rather than a robot.
A consultant at work my workplace brought two dogs, kept them in a 
nearby room during meeting and they pee on the floor. Machine dog eat 
oil and shit screw is much better.

The problem is the complexity.  It requires some advanced math and the
computer has to be able to run thousands or likely millions of simulations
of the entire machine per second.   This is maybe why we don't see
research on this done in the 1990s or 2000s.   It is a good use for a
6-core Intel i9 CPU


Read model based control theory at University. Non-linear system may be 
linearized around working point while linear system may be stated 
directly. In both cases it will be a system on matrix form. There are 
standard methods to calculate feed-forward once model have been stated. 
For servo motors rather simple calculations give fast dynamic response 
though it might be possible to get more accurate control by modeling 
more details and improve feed-forward.



Nicklas SB Karlsson



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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

The below is exactly true.  The problem is that PID is widely used and PID
is only "reactive" it can only deal with what has already happened and the
time lag is the source of oscillations.In the past, PID was the only
control option because we had limited computing power.   People are
starting to use MPC for motion control now.  MPC is predictive and can
account for "spring back", backlash and the time it will take to
decelerate.   But it does require modern compute power.   If you google,
you find many papers on MPC applied to milling machines starting in about
2010.

Eventually, this will filter down to the open-source DIY hobby community.
If you have ever seen a machine running with this kind of controller it is
visible even just looking at it by eye, the machine looks "alive" and moves
more like a human or a dog rather than a robot.   It is hard to describe
but it comes from "knowing" what is about to happen and taking the future
half-second or so into account.The control will take action to prevent
oscillation or spring because it is predictive, not reactive.  This is
in use now for some years, it's not speculative.

The problem is the complexity.  It requires some advanced math and the
computer has to be able to run thousands or likely millions of simulations
of the entire machine per second.   This is maybe why we don't see
research on this done in the 1990s or 2000s.   It is a good use for a
6-core Intel i9 CPU

On Sun, May 2, 2021 at 7:22 AM Gene Heskett  wrote:

>
> That is the unmentioned in polite company problem associated with glass
> scales as even resolvers aren't completely instant. The rssolution of it
> might include a higher frequency than 1 kilohertz for the servo loop.
> Stepgen based feedback doesn't have that lag. They report the position
> they've sent to the motors, no lag other than the quantization of the 1
> kilohertz servo loop.


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Sunday 02 May 2021 09:29:09 dave engvall wrote:

> Hi Gene,
>
> Your   comments on the servo-stepper are interesting. How well would
> they drive a BP sized mill?

I can't think of a GOOD reason, other than the mass of the knee would 
probably need some belt reduction in the knee. 3NM is in the 425 OZ/IN 
range and drives my GO704 at 70 or more IPM.  XY would be std ball 
screws of course.
>
> I'm thinking about picking up one to play with.
>
> Any reason you know of that they could not be used with and external
> encoder, eg glass scale for position?

None, it would be two different feedback paths that don't need mixing, 
let the motor and controller be run by the TP, and let the scales tell 
the TP where its at. PID's optional, all it would be is an additional 
rubber band in the control loop. I have no PID's in the sheldon config 
at all. Motion tells the motors what to do and they just do it. Feedback 
comes from the stepgen, and the motors do as they are told.  And if 
either can't do it, they stop linuxcnc in its tracks, litterally without 
a mark on the work that isn't springback.  Whats not to like?

The only problem I can see would be the time lag in the scales, they 
would have to be real time. Any lag would translate to overshoot and 
possible oscillation.  That would limit the useable accels of the 
machine as the TP or moiion would have to be able to anticipate the = 
point before it got there.

That is the unmentioned in polite company problem associated with glass 
scales as even resolvers aren't completely instant. The rssolution of it 
might include a higher frequency than 1 kilohertz for the servo loop.  
Stepgen based feedback doesn't have that lag. They report the position 
they've sent to the motors, no lag other than the quantization of the 1 
kilohertz servo loop.  And if the motors can't do it, they stop linuxcnc 
quite close to instantly.  You of course have to hook all that up in the 
hal file.

> Dave
>
> On 05/01/2021 05:51 PM, Gene Heskett wrote:
> > On Saturday 01 May 2021 12:34:01 Chris Albertson wrote:
> >> Gene,
> >>
> >> I did a search on the part number to gave and, they look really
> >> good but cost $400 per axis vs about $60 for what I have.   Yes,
> >> they are much better.Did you find a better deal?
> >
> > Egad, where are you looking? 6 months ago I bought 4 of them in two
> > orders thru ebay, 3 3NM's and a 2NM, and paid about $130 USD per
> > axis.
> >
> >  >wEZdaQa5B>
> >
> > 85$ copy, but $45 shipping.  So $130/axis, discounts for 3 or more.
> >
> > Cheers, Gene Heskett


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Saturday 01 May 2021 12:34:01 Chris Albertson wrote:

> Gene,
>
> I did a search on the part number to gave and, they look really good
> but cost $400 per axis vs about $60 for what I have.   Yes, they are
> much better.Did you find a better deal?
>
Egad, where are you looking? 6 months ago I bought 4 of them in two 
orders thru ebay, 3 3NM's and a 2NM, and paid about $130 USD per axis.



85$ copy, but $45 shipping.  So $130/axis, discounts for 3 or more.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Saturday 01 May 2021 12:25:12 Kenneth Lerman wrote:

> Has anyone tried using polypropylene  for the flex component? I
> believe PP is used for live hinges.
>
If refering to whats commony called TPU, yes, abject failure as its too 
flexible and just folds up.  Its good for those squeeze it coin purses 
though, and I may make some bigger ones to see if they'll sell as the 
one I have in my pocket is bursting with less than 2 dollars in small 
change in it.

> Ken
> Kenneth Lerman
> 55 Main Street
> Newtown, CT 06470
>
> On Fri, Apr 30, 2021 at 11:26 PM  wrote:
> > I haven't been following your project recently but am intrigued by
> > "And it turns the armature easy enough the 3NM 3 phase motor (those
> > are magic folks,
> > running 50C cooler than 2 phase stuff) I'll use will not be a bit
> > overstressed." Where did you end up getting your motors and what are
> > you using for drivers?
> >
> > -Original Message-
> > From: Gene Heskett 
> > Sent: April 30, 2021 10:45 PM
> > To: emc-users@lists.sourceforge.net
> > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> >
> > On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:
> > > 202,200 for the outside spline and the flex gear is 200.  In this
> > > situation - the 202 tooth spline is stationary to the stepper. 
> > > The 200 tooth outside spline is mounted to the faceplate.  In this
> > > layout - the ratio apears to be 101:1
> > >
> > > In this situation the stepper motor and the face plate spin the
> > > same direction.
> > >
> > > With the same set of outside spines swapped - the ratio is 100:1
> > >
> > > I am sure Andy can explain it.  It doesn't make sense to me.
> > >
> > > Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> > >
> > > sam
> >
> > I am running some behind you Sam, with my project, having printer
> > problems kills time and money. Finally settled on an ender 5 Plus,
> > which is working passably well but I've wasted $3k getting there.
> >
> > Any way, I changed the design some from yours, to a 30/1 because
> > those big spines print better, and by making my own bearings in
> > openscad, useing crosman bb's for balls. I put a huge one with over
> > 150 loose bb's directly on the outside of the moving spline, with
> > only the lip of the output coupling disc (printed of course)
> > interposed. And the floating spline has 3 more of those, sized for a
> > good friction fit inside that spline, with both the spline and the
> > bearings made as thin as practical to improve the flex life, and I
> > just took the eliptical armature off the build plate and wiggled
> > in into those 3 bearings inside the loose spline, so thats the
> > driver armature, no commercial ball bearings anyplace like yours. 
> > I've made the 8mm hole in the plastic for the motor shaft into a
> > prominent D-flat, and used a cbn wheel to make the flat much wider
> > on the motor shaft, and this armature will be driven onto the motor
> > shaft without any grub screws at all.
> > No clue how long it will run before it bores that hole out and I
> > have to make an alu inner for it. :(
> >
> > But I just now assembled it without the motor, turning the armature
> > by hand,
> > and it works, with no detectable backlash. And it turns the armature
> > easy enough the 3NM 3 phase motor (those are magic folks, running
> > 50C cooler than
> > 2 phase stuff) I'll use will not be a bit overstressed.  Those bb's
> > will pound the plastic smooth and get smoother with use.
> >
> > So now its time to finish the output shaft, and make the rest of the
> > housing. Which will be supported by the big bearing at the spline
> > end, and 4
> > of the printed bearings at the load end. I've got the motor end
> > gnawed out of some 1" stock I had, and I bought a foot of 3.125"
> > thick by 6" wide stuff
> > so I can make 2 output housings. That showed me the current price
> > for extruded alu, scary. I also bought enough rod to make about 4
> > output shafts,
> > over $200. And I've a spare 4" chuck from a TLM upgrade to a 5" to
> > use on it. Or better yet, buy another 5" from LMS.
> > So I'll get there, if I don't fall over first. At my age, thats
> > always a possibility.
> >
> > I'll try to get some pix of what I've got so far, put up on my web
> > page over
> > the weekend. Along with some of the openscad source files.
> >
> > As usual

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[andrew beck]

John.  I love the Chinese servos too.

And totally agree going direct to manafacture is much better.

I buy my servos with absolute encoders now.

130 ppr I think.  Or might be 13.

Just a basic 750w servo 220v servo drive plus motor costs me about $220 usd
last I checked.  (this is with just standard 2500ppr encoders)

I normally buy bigger ones like 3kw

Absolute encoders are a extra 50usd


And service is amazing.

Case in point I was setting up some kollmorgen servo star drives last
week.  Support was nothing like as good as the Chinese support lol.  (they
will do anything to help)

I'm thinking I Might bring in a pallet load to New Zealand and sell them
here as shipping by air is so expensive.

On Sun, 2 May 2021, 5:09 AM John Dammeyer,  wrote:

> > From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> > To: Enhanced Machine Controller (EMC)
> > Gene,
> >
> > I did a search on the part number to gave and, they look really good but
> > cost $400 per axis vs about $60 for what I have.   Yes, they are much
> > better.Did you find a better deal?
> >
> > Question for the group:
> > Assuming that you need about 3NM holding torque, what will $400 get you
> if
> > you want to use a servo motor?   I'm thinking that these 3-phase closed
> > loop steppers are more comparable in performance and price to servos than
> > to cheap steppers.   Anyone have a link to a source of small-size Chinese
> > servos and matching drivers.
> >
>
> 
> Yes.  I've been raving about the Bergerda series of AC Servos for a year
> now.  I have a 1.8kW running the mill spindle and a 750W (2.39NM) running
> the knee (19mm shaft size) which cost just under $300.
> http://en.bergerda.com/
>
> I also cast a mount and tried one of the 400W (1.25NM) units on the X axis
> and it was flawless too.  But at the moment my cabinet won't fit the drives
> compared to the DC Servo HP_UHU drives and I didn't want to swerve in
> another direction until the mill was completely converted. When I change to
> ball screws I'll also replace the two DC Brushed motors which are huge in
> comparative size to the AC servos.
>
> They come in various flavours and sizes (ie frame/rpm/torque/shaft size)
> and all run on 220VAC.  Pricing out from
> https://www.automationtechnologiesinc.com/products-page/ac-servo-motors
>
> the same DC brushed servo setup that I have comes out way more expensive
> than the AC servos when you add the driver and encoder and cable and DC
> power supply with one caveat.
>
> https://www.automationtechnologiesinc.com/products-page/dc-servo-motor/nema34-1125ozin-dual-shaft-servo-motor
>
> Shipping.  Bergerda is not a aliexpress reseller but the actual
> manufacturer so payments go through Alibaba and they won't do slow mail
> deliver.  Must be FedEx tracked therefore one motor can be very expensive.
> A big enough order could be done surface for considerable savings.
>
> I've been trying to connect them up with a North American supplier but so
> far no luck.
>
> Anyway, I bought extra 400W units for the eventual conversion to ball
> screws and one to replace the stepper on the lathe.   The drives all run on
> 220VAC which can be an issue if you only have 110VAC available.
>
> Now why servos instead of close loop steppers?  First the steppers still
> can stall at higher RPM so like standard steppers they are oriented to
> direct drive and slower rpm which means no torque multiplication with
> reduction belt drive. That generally means using a larger motor but they
> are definitely stable.  I used a CANopen commercial unit a while back that
> was impressive although eventually we upgraded to a German J1939 controlled
> AC Servo.
>
> The biggest downside other than rpm is they are still stepper motors and
> noisy whereas the AC Servos are quiet.  Dead quiet.   And support has been
> excellent with one of their engineers even making an iPhone video of the
> button press sequences of the display to set up some parameters when I was
> having trouble.
>
> Oh one other thing that I did verify.  Most of the cheap Aliexpress AC
> servos out there use cheap encoders.  Bergerda made a point of mentioning
> the use high end Japanese encoders.  So I took the cover off the end of the
> motor and grabbed the part number and name.  Yes indeed.  Japanese
> manufacturer and in singles through Alibaba came in at 3x the price of the
> cheap Aliexpress encoders.   So with cheap you get what you pay for I guess.
>
> 
>
> John Dammeyer
>
>
> > Next idea...
> > I looked up Gene's part and the motor/controler is sold as a set.  I can
> > see why.   But I see I can buy a 3-phase stepper motor for about $100.
>  So
> > we pay quite a lot for the driver and encoder.   I can buy a 1000 line
> > encoder for under $20 and close the loop with a $4 microcontroller and
> > three h-bridges.  I've done this many times using DC brushed gear motors.
> >  (My use case is robotics but it's identical to a multi-axis mill.)
> >
> > On Sat, May 1, 2021 at 6:30 AM Gene 

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Kenneth Lerman]

Has anyone tried using polypropylene  for the flex component? I believe PP
is used for live hinges.

Ken
Kenneth Lerman
55 Main Street
Newtown, CT 06470



On Fri, Apr 30, 2021 at 11:26 PM  wrote:

> I haven't been following your project recently but am intrigued by "And it
> turns the armature easy enough the 3NM 3 phase motor (those are magic
> folks,
> running 50C cooler than 2 phase stuff) I'll use will not be a bit
> overstressed." Where did you end up getting your motors and what are you
> using for drivers?
>
> -Original Message-
> From: Gene Heskett 
> Sent: April 30, 2021 10:45 PM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
>
> On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:
>
> > 202,200 for the outside spline and the flex gear is 200.  In this
> > situation - the 202 tooth spline is stationary to the stepper.  The
> > 200 tooth outside spline is mounted to the faceplate.  In this layout
> > - the ratio apears to be 101:1
> >
> > In this situation the stepper motor and the face plate spin the same
> > direction.
> >
> > With the same set of outside spines swapped - the ratio is 100:1
> >
> > I am sure Andy can explain it.  It doesn't make sense to me.
> >
> > Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> >
> > sam
> I am running some behind you Sam, with my project, having printer problems
> kills time and money. Finally settled on an ender 5 Plus, which is working
> passably well but I've wasted $3k getting there.
>
> Any way, I changed the design some from yours, to a 30/1 because those big
> spines print better, and by making my own bearings in openscad, useing
> crosman bb's for balls. I put a huge one with over 150 loose bb's directly
> on the outside of the moving spline, with only the lip of the output
> coupling disc (printed of course) interposed. And the floating spline has 3
> more of those, sized for a good friction fit inside that spline, with both
> the spline and the bearings made as thin as practical to improve the flex
> life, and I just took the eliptical armature off the build plate and
> wiggled
> in into those 3 bearings inside the loose spline, so thats the driver
> armature, no commercial ball bearings anyplace like yours.  I've made the
> 8mm hole in the plastic for the motor shaft into a prominent D-flat, and
> used a cbn wheel to make the flat much wider on the motor shaft, and this
> armature will be driven onto the motor shaft without any grub screws at
> all.
> No clue how long it will run before it bores that hole out and I have to
> make an alu inner for it. :(
>
> But I just now assembled it without the motor, turning the armature by
> hand,
> and it works, with no detectable backlash. And it turns the armature easy
> enough the 3NM 3 phase motor (those are magic folks, running 50C cooler
> than
> 2 phase stuff) I'll use will not be a bit overstressed.  Those bb's will
> pound the plastic smooth and get smoother with use.
>
> So now its time to finish the output shaft, and make the rest of the
> housing. Which will be supported by the big bearing at the spline end, and
> 4
> of the printed bearings at the load end. I've got the motor end gnawed out
> of some 1" stock I had, and I bought a foot of 3.125" thick by 6" wide
> stuff
> so I can make 2 output housings. That showed me the current price for
> extruded alu, scary. I also bought enough rod to make about 4 output
> shafts,
> over $200. And I've a spare 4" chuck from a TLM upgrade to a 5" to use on
> it. Or better yet, buy another 5" from LMS.
> So I'll get there, if I don't fall over first. At my age, thats always a
> possibility.
>
> I'll try to get some pix of what I've got so far, put up on my web page
> over
> the weekend. Along with some of the openscad source files.
>
> As usual, this stuff keeps me alone, safe, and out of the bars. :-)
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
>
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>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

> From: Chris Albertson [mailto:albertson.ch...@gmail.com]
> To: Enhanced Machine Controller (EMC)
> Gene,
> 
> I did a search on the part number to gave and, they look really good but
> cost $400 per axis vs about $60 for what I have.   Yes, they are much
> better.Did you find a better deal?
> 
> Question for the group:
> Assuming that you need about 3NM holding torque, what will $400 get you if
> you want to use a servo motor?   I'm thinking that these 3-phase closed
> loop steppers are more comparable in performance and price to servos than
> to cheap steppers.   Anyone have a link to a source of small-size Chinese
> servos and matching drivers.
> 


Yes.  I've been raving about the Bergerda series of AC Servos for a year now.  
I have a 1.8kW running the mill spindle and a 750W (2.39NM) running the knee 
(19mm shaft size) which cost just under $300.   
http://en.bergerda.com/

I also cast a mount and tried one of the 400W (1.25NM) units on the X axis and 
it was flawless too.  But at the moment my cabinet won't fit the drives 
compared to the DC Servo HP_UHU drives and I didn't want to swerve in another 
direction until the mill was completely converted. When I change to ball screws 
I'll also replace the two DC Brushed motors which are huge in comparative size 
to the AC servos.

They come in various flavours and sizes (ie frame/rpm/torque/shaft size) and 
all run on 220VAC.  Pricing out from 
https://www.automationtechnologiesinc.com/products-page/ac-servo-motors

the same DC brushed servo setup that I have comes out way more expensive than 
the AC servos when you add the driver and encoder and cable and DC power supply 
with one caveat.  
https://www.automationtechnologiesinc.com/products-page/dc-servo-motor/nema34-1125ozin-dual-shaft-servo-motor

Shipping.  Bergerda is not a aliexpress reseller but the actual manufacturer so 
payments go through Alibaba and they won't do slow mail deliver.  Must be FedEx 
tracked therefore one motor can be very expensive.  A big enough order could be 
done surface for considerable savings.

I've been trying to connect them up with a North American supplier but so far 
no luck.  

Anyway, I bought extra 400W units for the eventual conversion to ball screws 
and one to replace the stepper on the lathe.   The drives all run on 220VAC 
which can be an issue if you only have 110VAC available.

Now why servos instead of close loop steppers?  First the steppers still can 
stall at higher RPM so like standard steppers they are oriented to direct drive 
and slower rpm which means no torque multiplication with reduction belt drive. 
That generally means using a larger motor but they are definitely stable.  I 
used a CANopen commercial unit a while back that was impressive although 
eventually we upgraded to a German J1939 controlled AC Servo.

The biggest downside other than rpm is they are still stepper motors and noisy 
whereas the AC Servos are quiet.  Dead quiet.   And support has been excellent 
with one of their engineers even making an iPhone video of the button press 
sequences of the display to set up some parameters when I was having trouble.

Oh one other thing that I did verify.  Most of the cheap Aliexpress AC servos 
out there use cheap encoders.  Bergerda made a point of mentioning the use high 
end Japanese encoders.  So I took the cover off the end of the motor and 
grabbed the part number and name.  Yes indeed.  Japanese manufacturer and in 
singles through Alibaba came in at 3x the price of the cheap Aliexpress 
encoders.   So with cheap you get what you pay for I guess.



John Dammeyer


> Next idea...
> I looked up Gene's part and the motor/controler is sold as a set.  I can
> see why.   But I see I can buy a 3-phase stepper motor for about $100.   So
> we pay quite a lot for the driver and encoder.   I can buy a 1000 line
> encoder for under $20 and close the loop with a $4 microcontroller and
> three h-bridges.  I've done this many times using DC brushed gear motors.
>  (My use case is robotics but it's identical to a multi-axis mill.)
> 
> On Sat, May 1, 2021 at 6:30 AM Gene Heskett  wrote:
> 
> > On Saturday 01 May 2021 08:35:12 Thaddeus Waldner wrote:
> >
> > > So these are actual stepper motors and not 3-phase BLDC motors with
> > > step/direction input?
> >
> > yes, and while I said a step loss will stop them it has to exist for an
> > unspecified time frame. You can fasten them down, put a vice grip on the
> > shaft and turn them 1/4 turn before they error, they will resist
> > mightily and if you let go of the vice grips quick enough, they'll catch
> > up to a zero error and just keep on trucking. I can, creeping along with
> > my jog dials, run a carbide tipped tool into a stationary chuck jaw, and
> > when its found itself jammed, it shuts down the output drivers and
> > bounces about 10 thou clear of the chuck, all without damageing the chip
> > in the tool.  The machine will obviously need re-homed as I have the
> > volatile option set 

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

Gene,

I did a search on the part number to gave and, they look really good but
cost $400 per axis vs about $60 for what I have.   Yes, they are much
better.Did you find a better deal?

Question for the group:
Assuming that you need about 3NM holding torque, what will $400 get you if
you want to use a servo motor?   I'm thinking that these 3-phase closed
loop steppers are more comparable in performance and price to servos than
to cheap steppers.   Anyone have a link to a source of small-size Chinese
servos and matching drivers.

Next idea...
I looked up Gene's part and the motor/controler is sold as a set.  I can
see why.   But I see I can buy a 3-phase stepper motor for about $100.   So
we pay quite a lot for the driver and encoder.   I can buy a 1000 line
encoder for under $20 and close the loop with a $4 microcontroller and
three h-bridges.  I've done this many times using DC brushed gear motors.
 (My use case is robotics but it's identical to a multi-axis mill.)

On Sat, May 1, 2021 at 6:30 AM Gene Heskett  wrote:

> On Saturday 01 May 2021 08:35:12 Thaddeus Waldner wrote:
>
> > So these are actual stepper motors and not 3-phase BLDC motors with
> > step/direction input?
>
> yes, and while I said a step loss will stop them it has to exist for an
> unspecified time frame. You can fasten them down, put a vice grip on the
> shaft and turn them 1/4 turn before they error, they will resist
> mightily and if you let go of the vice grips quick enough, they'll catch
> up to a zero error and just keep on trucking. I can, creeping along with
> my jog dials, run a carbide tipped tool into a stationary chuck jaw, and
> when its found itself jammed, it shuts down the output drivers and
> bounces about 10 thou clear of the chuck, all without damageing the chip
> in the tool.  The machine will obviously need re-homed as I have the
> volatile option set in the .ini file.  Thats a 25mm z screw, but my x
> screw is only an 8mm, so while its wired I've deferred to the size of
> the screw and the possibility of damaging it, and not tested it
> similarly with its shorter, 2NM rated motor. That screw today seems to
> be made of pure unobtainium, its half of one of a triplet I bought from
> Stuart St. about 15 or more years ago to cnc the smallest hf mill.
>
> > I always assumed that it’s the latter, with the difference being lost
> > in translation.
>
> So did I, but installing one, replacing a stepper that ran burn you hand
> hot, and finding it stone cold after half an hour powered up but the
> only move was homing the axis was quite the eye opener, the motors
> holding current is determined by the encoder error.  No error=not enough
> holding currant to make feelable heat. You think its shut down, until
> you try to turn it...
>
> [...]
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Saturday 01 May 2021 08:35:12 Thaddeus Waldner wrote:

> So these are actual stepper motors and not 3-phase BLDC motors with
> step/direction input?

yes, and while I said a step loss will stop them it has to exist for an 
unspecified time frame. You can fasten them down, put a vice grip on the 
shaft and turn them 1/4 turn before they error, they will resist 
mightily and if you let go of the vice grips quick enough, they'll catch 
up to a zero error and just keep on trucking. I can, creeping along with 
my jog dials, run a carbide tipped tool into a stationary chuck jaw, and 
when its found itself jammed, it shuts down the output drivers and 
bounces about 10 thou clear of the chuck, all without damageing the chip 
in the tool.  The machine will obviously need re-homed as I have the 
volatile option set in the .ini file.  Thats a 25mm z screw, but my x 
screw is only an 8mm, so while its wired I've deferred to the size of 
the screw and the possibility of damaging it, and not tested it 
similarly with its shorter, 2NM rated motor. That screw today seems to 
be made of pure unobtainium, its half of one of a triplet I bought from 
Stuart St. about 15 or more years ago to cnc the smallest hf mill.

> I always assumed that it’s the latter, with the difference being lost
> in translation.

So did I, but installing one, replacing a stepper that ran burn you hand 
hot, and finding it stone cold after half an hour powered up but the 
only move was homing the axis was quite the eye opener, the motors 
holding current is determined by the encoder error.  No error=not enough 
holding currant to make feelable heat. You think its shut down, until 
you try to turn it...

[...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Thaddeus Waldner]

So these are actual stepper motors and not 3-phase BLDC motors with 
step/direction input?

I always assumed that it’s the latter, with the difference being lost in 
translation.


> On Apr 30, 2021, at 11:23 PM, Gene Heskett  wrote:
> 
> On Friday 30 April 2021 23:25:43 ken.stra...@gmail.com wrote:
> 
>> I haven't been following your project recently but am intrigued by
>> "And it turns the armature easy enough the 3NM 3 phase motor (those
>> are magic folks, running 50C cooler than 2 phase stuff) I'll use will
>> not be a bit overstressed." Where did you end up getting your motors
>> and what are you using for drivers?
>> 
> Ebay for all of them.  There are 2 phase with feedback but they work at 
> full motor currants all the time. The only driver that counts and really 
> is 3 phase is the LCDA357H although I expect it will grow bigger brother 
> versions as time goes by and folks become aware of them. The chinese are 
> not heavly advertizing that, the difference getting lost in the 
> translation or ???.
> 
> Motor wires are labeled UVW just like a vfd. And a full step is 1.2 
> degrees, not 1.8.
> 
> An encoder on the back of the motor talks to the driver, not to LCNC, and 
> you drive them exactly as you would any other stepper setup.
> 
> Step speeds are still limited by the input opto's to maybe 250 kilohertz. 
> It, the LCDA3576H driver is small, about the size of a 100 mil pack of 
> smokes, has no currant setting switches because the motor current is 
> determined by the magnitude of the error.  Makes it at least 5x more 
> efficient. Rated at 20-50 VDC input, there are 1,2, & 3 NM sizes that I 
> know of right now. Running my 11x54 Sheldon with rapids 2x faster than 
> the 2 phase stuff I took off, motor heating might be 5F. And if they 
> lose a step, they have an error out that can shut down LCNC with the 
> e-stop circuit.
> 
> Highly recommended by great, great, grandpa Gene as a genuine improvement 
> in stepper technology.
> 
>> -----Original Message-
>> From: Gene Heskett 
>> Sent: April 30, 2021 10:45 PM
>> To: emc-users@lists.sourceforge.net
>> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
>> 
>>> On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:
>>> 202,200 for the outside spline and the flex gear is 200.  In this
>>> situation - the 202 tooth spline is stationary to the stepper.  The
>>> 200 tooth outside spline is mounted to the faceplate.  In this
>>> layout - the ratio apears to be 101:1
>>> 
>>> In this situation the stepper motor and the face plate spin the same
>>> direction.
>>> 
>>> With the same set of outside spines swapped - the ratio is 100:1
>>> 
>>> I am sure Andy can explain it.  It doesn't make sense to me.
>>> 
>>> Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
>>> 
>>> sam
>> 
>> I am running some behind you Sam, with my project, having printer
>> problems kills time and money. Finally settled on an ender 5 Plus,
>> which is working passably well but I've wasted $3k getting there.
>> 
>> Any way, I changed the design some from yours, to a 30/1 because those
>> big spines print better, and by making my own bearings in openscad,
>> useing crosman bb's for balls. I put a huge one with over 150 loose
>> bb's directly on the outside of the moving spline, with only the lip
>> of the output coupling disc (printed of course) interposed. And the
>> floating spline has 3 more of those, sized for a good friction fit
>> inside that spline, with both the spline and the bearings made as thin
>> as practical to improve the flex life, and I just took the eliptical
>> armature off the build plate and wiggled in into those 3 bearings
>> inside the loose spline, so thats the driver armature, no commercial
>> ball bearings anyplace like yours.  I've made the 8mm hole in the
>> plastic for the motor shaft into a prominent D-flat, and used a cbn
>> wheel to make the flat much wider on the motor shaft, and this
>> armature will be driven onto the motor shaft without any grub screws
>> at all. No clue how long it will run before it bores that hole out and
>> I have to make an alu inner for it. :(
>> 
>> But I just now assembled it without the motor, turning the armature by
>> hand, and it works, with no detectable backlash. And it turns the
>> armature easy enough the 3NM 3 phase motor (those are magic folks,
>> running 50C cooler than 2 phase stuff) I'll use will not be a bit
>> overstressed.  Those bb's will pound the plastic smooth and get
>> smoother w

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Friday 30 April 2021 23:25:43 ken.stra...@gmail.com wrote:

> I haven't been following your project recently but am intrigued by
> "And it turns the armature easy enough the 3NM 3 phase motor (those
> are magic folks, running 50C cooler than 2 phase stuff) I'll use will
> not be a bit overstressed." Where did you end up getting your motors
> and what are you using for drivers?
>
Ebay for all of them.  There are 2 phase with feedback but they work at 
full motor currants all the time. The only driver that counts and really 
is 3 phase is the LCDA357H although I expect it will grow bigger brother 
versions as time goes by and folks become aware of them. The chinese are 
not heavly advertizing that, the difference getting lost in the 
translation or ???.

Motor wires are labeled UVW just like a vfd. And a full step is 1.2 
degrees, not 1.8.

An encoder on the back of the motor talks to the driver, not to LCNC, and 
you drive them exactly as you would any other stepper setup.

Step speeds are still limited by the input opto's to maybe 250 kilohertz. 
It, the LCDA3576H driver is small, about the size of a 100 mil pack of 
smokes, has no currant setting switches because the motor current is 
determined by the magnitude of the error.  Makes it at least 5x more 
efficient. Rated at 20-50 VDC input, there are 1,2, & 3 NM sizes that I 
know of right now. Running my 11x54 Sheldon with rapids 2x faster than 
the 2 phase stuff I took off, motor heating might be 5F. And if they 
lose a step, they have an error out that can shut down LCNC with the 
e-stop circuit.

Highly recommended by great, great, grandpa Gene as a genuine improvement 
in stepper technology.

> -Original Message-
> From: Gene Heskett 
> Sent: April 30, 2021 10:45 PM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
>
> On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:
> > 202,200 for the outside spline and the flex gear is 200.  In this
> > situation - the 202 tooth spline is stationary to the stepper.  The
> > 200 tooth outside spline is mounted to the faceplate.  In this
> > layout - the ratio apears to be 101:1
> >
> > In this situation the stepper motor and the face plate spin the same
> > direction.
> >
> > With the same set of outside spines swapped - the ratio is 100:1
> >
> > I am sure Andy can explain it.  It doesn't make sense to me.
> >
> > Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> >
> > sam
>
> I am running some behind you Sam, with my project, having printer
> problems kills time and money. Finally settled on an ender 5 Plus,
> which is working passably well but I've wasted $3k getting there.
>
> Any way, I changed the design some from yours, to a 30/1 because those
> big spines print better, and by making my own bearings in openscad,
> useing crosman bb's for balls. I put a huge one with over 150 loose
> bb's directly on the outside of the moving spline, with only the lip
> of the output coupling disc (printed of course) interposed. And the
> floating spline has 3 more of those, sized for a good friction fit
> inside that spline, with both the spline and the bearings made as thin
> as practical to improve the flex life, and I just took the eliptical
> armature off the build plate and wiggled in into those 3 bearings
> inside the loose spline, so thats the driver armature, no commercial
> ball bearings anyplace like yours.  I've made the 8mm hole in the
> plastic for the motor shaft into a prominent D-flat, and used a cbn
> wheel to make the flat much wider on the motor shaft, and this
> armature will be driven onto the motor shaft without any grub screws
> at all. No clue how long it will run before it bores that hole out and
> I have to make an alu inner for it. :(
>
> But I just now assembled it without the motor, turning the armature by
> hand, and it works, with no detectable backlash. And it turns the
> armature easy enough the 3NM 3 phase motor (those are magic folks,
> running 50C cooler than 2 phase stuff) I'll use will not be a bit
> overstressed.  Those bb's will pound the plastic smooth and get
> smoother with use.
>
> So now its time to finish the output shaft, and make the rest of the
> housing. Which will be supported by the big bearing at the spline end,
> and 4 of the printed bearings at the load end. I've got the motor end
> gnawed out of some 1" stock I had, and I bought a foot of 3.125" thick
> by 6" wide stuff so I can make 2 output housings. That showed me the
> current price for extruded alu, scary. I also bought enough rod to
> make about 4 output shafts, over $200. And I've a spare 4" chuck from
> a TLM upgrade to a 5" to use on it. Or bett

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[ken.strauss]

I haven't been following your project recently but am intrigued by "And it
turns the armature easy enough the 3NM 3 phase motor (those are magic folks,
running 50C cooler than 2 phase stuff) I'll use will not be a bit
overstressed." Where did you end up getting your motors and what are you
using for drivers?

-Original Message-
From: Gene Heskett  
Sent: April 30, 2021 10:45 PM
To: emc-users@lists.sourceforge.net
Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?

On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:

> 202,200 for the outside spline and the flex gear is 200.  In this 
> situation - the 202 tooth spline is stationary to the stepper.  The
> 200 tooth outside spline is mounted to the faceplate.  In this layout
> - the ratio apears to be 101:1
>
> In this situation the stepper motor and the face plate spin the same 
> direction.
>
> With the same set of outside spines swapped - the ratio is 100:1
>
> I am sure Andy can explain it.  It doesn't make sense to me.
>
> Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
>
> sam
I am running some behind you Sam, with my project, having printer problems
kills time and money. Finally settled on an ender 5 Plus, which is working
passably well but I've wasted $3k getting there.

Any way, I changed the design some from yours, to a 30/1 because those big
spines print better, and by making my own bearings in openscad, useing
crosman bb's for balls. I put a huge one with over 150 loose bb's directly
on the outside of the moving spline, with only the lip of the output
coupling disc (printed of course) interposed. And the floating spline has 3
more of those, sized for a good friction fit inside that spline, with both
the spline and the bearings made as thin as practical to improve the flex
life, and I just took the eliptical armature off the build plate and wiggled
in into those 3 bearings inside the loose spline, so thats the driver
armature, no commercial ball bearings anyplace like yours.  I've made the
8mm hole in the plastic for the motor shaft into a prominent D-flat, and
used a cbn wheel to make the flat much wider on the motor shaft, and this
armature will be driven onto the motor shaft without any grub screws at all.
No clue how long it will run before it bores that hole out and I have to
make an alu inner for it. :(

But I just now assembled it without the motor, turning the armature by hand,
and it works, with no detectable backlash. And it turns the armature easy
enough the 3NM 3 phase motor (those are magic folks, running 50C cooler than
2 phase stuff) I'll use will not be a bit overstressed.  Those bb's will
pound the plastic smooth and get smoother with use.

So now its time to finish the output shaft, and make the rest of the
housing. Which will be supported by the big bearing at the spline end, and 4
of the printed bearings at the load end. I've got the motor end gnawed out
of some 1" stock I had, and I bought a foot of 3.125" thick by 6" wide stuff
so I can make 2 output housings. That showed me the current price for
extruded alu, scary. I also bought enough rod to make about 4 output shafts,
over $200. And I've a spare 4" chuck from a TLM upgrade to a 5" to use on
it. Or better yet, buy another 5" from LMS.  
So I'll get there, if I don't fall over first. At my age, thats always a
possibility.

I'll try to get some pix of what I've got so far, put up on my web page over
the weekend. Along with some of the openscad source files.

As usual, this stuff keeps me alone, safe, and out of the bars. :-)

Cheers, Gene Heskett
--
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page <http://geneslinuxbox.net:6309/gene>


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:

> 202,200 for the outside spline and the flex gear is 200.  In this
> situation - the 202 tooth spline is stationary to the stepper.  The
> 200 tooth outside spline is mounted to the faceplate.  In this layout
> - the ratio apears to be 101:1
>
> In this situation the stepper motor and the face plate spin the same
> direction.
>
> With the same set of outside spines swapped - the ratio is 100:1
>
> I am sure Andy can explain it.  It doesn't make sense to me.
>
> Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
>
> sam
I am running some behind you Sam, with my project, having printer 
problems kills time and money. Finally settled on an ender 5 Plus, which 
is working passably well but I've wasted $3k getting there.

Any way, I changed the design some from yours, to a 30/1 because those 
big spines print better, and by making my own bearings in openscad, 
useing crosman bb's for balls. I put a huge one with over 150 loose bb's 
directly on the outside of the moving spline, with only the lip of the 
output coupling disc (printed of course) interposed. And the floating 
spline has 3 more of those, sized for a good friction fit inside that 
spline, with both the spline and the bearings made as thin as practical 
to improve the flex life, and I just took the eliptical armature off the 
build plate and wiggled in into those 3 bearings inside the loose 
spline, so thats the driver armature, no commercial ball bearings 
anyplace like yours.  I've made the 8mm hole in the plastic for the 
motor shaft into a prominent D-flat, and used a cbn wheel to make the 
flat much wider on the motor shaft, and this armature will be driven 
onto the motor shaft without any grub screws at all.  No clue how long 
it will run before it bores that hole out and I have to make an alu 
inner for it. :(

But I just now assembled it without the motor, turning the armature by 
hand, and it works, with no detectable backlash. And it turns the 
armature easy enough the 3NM 3 phase motor (those are magic folks, 
running 50C cooler than 2 phase stuff) I'll use will not be a bit 
overstressed.  Those bb's will pound the plastic smooth and get smoother 
with use.

So now its time to finish the output shaft, and make the rest of the 
housing. Which will be supported by the big bearing at the spline end, 
and 4 of the printed bearings at the load end. I've got the motor end 
gnawed out of some 1" stock I had, and I bought a foot of 3.125" thick 
by 6" wide stuff so I can make 2 output housings. That showed me the 
current price for extruded alu, scary. I also bought enough rod to make 
about 4 output shafts, over $200. And I've a spare 4" chuck from a TLM 
upgrade to a 5" to use on it. Or better yet, buy another 5" from LMS.  
So I'll get there, if I don't fall over first. At my age, thats always a 
possibility.

I'll try to get some pix of what I've got so far, put up on my web page 
over the weekend. Along with some of the openscad source files.

As usual, this stuff keeps me alone, safe, and out of the bars. :-)

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

https://www.youtube.com/watch?v=JSDu81jjYFs

On Mon, Mar 29, 2021 at 10:23 PM Sam Sokolik  wrote:

> ^  thanks andy.
>
> On Mon, Mar 29, 2021 at 10:23 PM Sam Sokolik  wrote:
>
>> http://electronicsam.com/images/greenmachine/IMG_20210329_220745.jpg
>>
>> On Sun, Mar 28, 2021 at 5:17 PM Sam Sokolik  wrote:
>>
>>> have not done any destructive testing - but finally grabbed an oem650
>>> drive so I can have full 4 axis to play with.  Seems to run the rotary
>>> atleast as good as the leadshine.
>>>
>>> http://electronicsam.com/images/greenmachine/IMG_20210328_165552.jpg
>>>
>>> On Wed, Mar 24, 2021 at 8:36 AM Sam Sokolik  wrote:
>>>
 I have a cheap chuck that is held on with 3 cap head screws.  My plan
 is to make a disk that registers the center of the faceplate and the inside
 lip of the chuck. - I don't remember the exact size..  about 4.5"

 On Tue, Mar 23, 2021 at 9:48 PM John Dammeyer 
 wrote:

>
>
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
> >
>
> So Sam,
> What's the diameter of the faceplate?
> And are you planning on mounting a chuck onto it?
>
> If so, all the front mount ones still need some sort of registration
> groove on the inner diameter of the mounting screws.
>
> Andy Pugh created a faceplate for his Harmonic drive that had camlock
> chuck capability.  This way he could move his 3 or 4 jaw chuck from the
> lathe to the 4th axis on the mill.
>
> In my case I have a South Bend Heavy 10L with the threaded spindle.
> Short of modifying it with some sort of locking nut or pin to prevent
> reverse rotation off the threads, I'm not sure putting a threaded nose 
> onto
> a 4th axis is a good idea.
>
> A smaller chuck on a faceplate that is threaded for the South bend but
> has screws and a registration groove for the 4th axis seems like an idea
> that might work.  I have 3" chucks for the Gingery Lathe but they are on 
> 16
> TPI threaded arbors.
>
> John Dammeyer
>
>
>
>
> ___
> Emc-users mailing list
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>


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

^  thanks andy.

On Mon, Mar 29, 2021 at 10:23 PM Sam Sokolik  wrote:

> http://electronicsam.com/images/greenmachine/IMG_20210329_220745.jpg
>
> On Sun, Mar 28, 2021 at 5:17 PM Sam Sokolik  wrote:
>
>> have not done any destructive testing - but finally grabbed an oem650
>> drive so I can have full 4 axis to play with.  Seems to run the rotary
>> atleast as good as the leadshine.
>>
>> http://electronicsam.com/images/greenmachine/IMG_20210328_165552.jpg
>>
>> On Wed, Mar 24, 2021 at 8:36 AM Sam Sokolik  wrote:
>>
>>> I have a cheap chuck that is held on with 3 cap head screws.  My plan is
>>> to make a disk that registers the center of the faceplate and the inside
>>> lip of the chuck. - I don't remember the exact size..  about 4.5"
>>>
>>> On Tue, Mar 23, 2021 at 9:48 PM John Dammeyer 
>>> wrote:
>>>


 > From: Sam Sokolik [mailto:samco...@gmail.com]
 > http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
 >

 So Sam,
 What's the diameter of the faceplate?
 And are you planning on mounting a chuck onto it?

 If so, all the front mount ones still need some sort of registration
 groove on the inner diameter of the mounting screws.

 Andy Pugh created a faceplate for his Harmonic drive that had camlock
 chuck capability.  This way he could move his 3 or 4 jaw chuck from the
 lathe to the 4th axis on the mill.

 In my case I have a South Bend Heavy 10L with the threaded spindle.
 Short of modifying it with some sort of locking nut or pin to prevent
 reverse rotation off the threads, I'm not sure putting a threaded nose onto
 a 4th axis is a good idea.

 A smaller chuck on a faceplate that is threaded for the South bend but
 has screws and a registration groove for the 4th axis seems like an idea
 that might work.  I have 3" chucks for the Gingery Lathe but they are on 16
 TPI threaded arbors.

 John Dammeyer




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>>>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

http://electronicsam.com/images/greenmachine/IMG_20210329_220745.jpg

On Sun, Mar 28, 2021 at 5:17 PM Sam Sokolik  wrote:

> have not done any destructive testing - but finally grabbed an oem650
> drive so I can have full 4 axis to play with.  Seems to run the rotary
> atleast as good as the leadshine.
>
> http://electronicsam.com/images/greenmachine/IMG_20210328_165552.jpg
>
> On Wed, Mar 24, 2021 at 8:36 AM Sam Sokolik  wrote:
>
>> I have a cheap chuck that is held on with 3 cap head screws.  My plan is
>> to make a disk that registers the center of the faceplate and the inside
>> lip of the chuck. - I don't remember the exact size..  about 4.5"
>>
>> On Tue, Mar 23, 2021 at 9:48 PM John Dammeyer 
>> wrote:
>>
>>>
>>>
>>> > From: Sam Sokolik [mailto:samco...@gmail.com]
>>> > http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
>>> >
>>>
>>> So Sam,
>>> What's the diameter of the faceplate?
>>> And are you planning on mounting a chuck onto it?
>>>
>>> If so, all the front mount ones still need some sort of registration
>>> groove on the inner diameter of the mounting screws.
>>>
>>> Andy Pugh created a faceplate for his Harmonic drive that had camlock
>>> chuck capability.  This way he could move his 3 or 4 jaw chuck from the
>>> lathe to the 4th axis on the mill.
>>>
>>> In my case I have a South Bend Heavy 10L with the threaded spindle.
>>> Short of modifying it with some sort of locking nut or pin to prevent
>>> reverse rotation off the threads, I'm not sure putting a threaded nose onto
>>> a 4th axis is a good idea.
>>>
>>> A smaller chuck on a faceplate that is threaded for the South bend but
>>> has screws and a registration groove for the 4th axis seems like an idea
>>> that might work.  I have 3" chucks for the Gingery Lathe but they are on 16
>>> TPI threaded arbors.
>>>
>>> John Dammeyer
>>>
>>>
>>>
>>>
>>> ___
>>> Emc-users mailing list
>>> Emc-users@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>>
>>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

have not done any destructive testing - but finally grabbed an oem650 drive
so I can have full 4 axis to play with.  Seems to run the rotary atleast as
good as the leadshine.

http://electronicsam.com/images/greenmachine/IMG_20210328_165552.jpg

On Wed, Mar 24, 2021 at 8:36 AM Sam Sokolik  wrote:

> I have a cheap chuck that is held on with 3 cap head screws.  My plan is
> to make a disk that registers the center of the faceplate and the inside
> lip of the chuck. - I don't remember the exact size..  about 4.5"
>
> On Tue, Mar 23, 2021 at 9:48 PM John Dammeyer 
> wrote:
>
>>
>>
>> > From: Sam Sokolik [mailto:samco...@gmail.com]
>> > http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
>> >
>>
>> So Sam,
>> What's the diameter of the faceplate?
>> And are you planning on mounting a chuck onto it?
>>
>> If so, all the front mount ones still need some sort of registration
>> groove on the inner diameter of the mounting screws.
>>
>> Andy Pugh created a faceplate for his Harmonic drive that had camlock
>> chuck capability.  This way he could move his 3 or 4 jaw chuck from the
>> lathe to the 4th axis on the mill.
>>
>> In my case I have a South Bend Heavy 10L with the threaded spindle.
>> Short of modifying it with some sort of locking nut or pin to prevent
>> reverse rotation off the threads, I'm not sure putting a threaded nose onto
>> a 4th axis is a good idea.
>>
>> A smaller chuck on a faceplate that is threaded for the South bend but
>> has screws and a registration groove for the 4th axis seems like an idea
>> that might work.  I have 3" chucks for the Gingery Lathe but they are on 16
>> TPI threaded arbors.
>>
>> John Dammeyer
>>
>>
>>
>>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

I have a cheap chuck that is held on with 3 cap head screws.  My plan is to
make a disk that registers the center of the faceplate and the inside lip
of the chuck. - I don't remember the exact size..  about 4.5"

On Tue, Mar 23, 2021 at 9:48 PM John Dammeyer 
wrote:

>
>
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
> >
>
> So Sam,
> What's the diameter of the faceplate?
> And are you planning on mounting a chuck onto it?
>
> If so, all the front mount ones still need some sort of registration
> groove on the inner diameter of the mounting screws.
>
> Andy Pugh created a faceplate for his Harmonic drive that had camlock
> chuck capability.  This way he could move his 3 or 4 jaw chuck from the
> lathe to the 4th axis on the mill.
>
> In my case I have a South Bend Heavy 10L with the threaded spindle.  Short
> of modifying it with some sort of locking nut or pin to prevent reverse
> rotation off the threads, I'm not sure putting a threaded nose onto a 4th
> axis is a good idea.
>
> A smaller chuck on a faceplate that is threaded for the South bend but has
> screws and a registration groove for the 4th axis seems like an idea that
> might work.  I have 3" chucks for the Gingery Lathe but they are on 16 TPI
> threaded arbors.
>
> John Dammeyer
>
>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

> From: Sam Sokolik [mailto:samco...@gmail.com]
> http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
> 

So Sam,
What's the diameter of the faceplate?  
And are you planning on mounting a chuck onto it?  

If so, all the front mount ones still need some sort of registration groove on 
the inner diameter of the mounting screws.  

Andy Pugh created a faceplate for his Harmonic drive that had camlock chuck 
capability.  This way he could move his 3 or 4 jaw chuck from the lathe to the 
4th axis on the mill.  

In my case I have a South Bend Heavy 10L with the threaded spindle.  Short of 
modifying it with some sort of locking nut or pin to prevent reverse rotation 
off the threads, I'm not sure putting a threaded nose onto a 4th axis is a good 
idea.

A smaller chuck on a faceplate that is threaded for the South bend but has 
screws and a registration groove for the 4th axis seems like an idea that might 
work.  I have 3" chucks for the Gingery Lathe but they are on 16 TPI threaded 
arbors.

John Dammeyer




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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

no - one way (current way with the 200 spline stationary with the stepper)
the stepper goes the same direction as the face plate.  The with the
outside splines swapped - stepper goes the opposite direction of the face
plate.

On Mon, Mar 22, 2021 at 12:08 PM John Dammeyer 
wrote:

> In both cases the direction is the same?  Like in real life?
>
> > -Original Message-
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > Sent: March-22-21 9:48 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> >
> > Makes sense.. :)
> >
> > On Mon, Mar 22, 2021 at 11:37 AM John Dammeyer 
> > wrote:
> >
> > > Using the math from that link below
> > > (202-200)/200=0.01 ==> inverted is 100:1.
> > >
> > > Done the other way...  If that's possible then
> > > (202-200)/202 = 0.0099009900... ==> inverted is 101:1
> > >
> > > John
> > >
> > > > -Original Message-----
> > > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > > > Sent: March-22-21 6:19 AM
> > > > To: Enhanced Machine Controller (EMC)
> > > > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> > > >
> > > > 202,200 for the outside spline and the flex gear is 200.  In this
> > > situation
> > > > - the 202 tooth spline is stationary to the stepper.  The 200 tooth
> > > outside
> > > > spline is mounted to the faceplate.  In this layout - the ratio
> apears to
> > > > be 101:1
> > > >
> > > > In this situation the stepper motor and the face plate spin the same
> > > > direction.
> > > >
> > > > With the same set of outside spines swapped - the ratio is 100:1
> > > >
> > > > I am sure Andy can explain it.  It doesn't make sense to me.
> > > >
> > > > Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> > > >
> > > > sam
> > > >
> > > > On Mon, Mar 22, 2021 at 12:58 AM John Dammeyer <
> jo...@autoartisans.com>
> > > > wrote:
> > > >
> > > > >
> > > > >
> > > > > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > > > > > So.   interesting..   I just swapped the gears..  Before my
> > > ratio was
> > > > > > 100:1.   Input scale was 1600step/rev * 100 = 16/360 =
> > > 444.444
> > > > > > input scale.
> > > > > >
> > > > > > Now I reversed the outside splines.   I thought - wow - I must be
> > > losing
> > > > > > steps - but i would aways come back to zero.   Finally though -
> > > maybe the
> > > > > > ratio was now 102:1 - no.  over shot.
> > > > > >
> > > > > > so the final solution seems to be 101:1  WTH?
> > > > > >
> > > > > > sam
> > > > >
> > > > > Hi Sam,
> > > > > I found this at:
> > > > > https://www.engineeringclicks.com/harmonic-drive/
> > > > >
> > > > > "The rate of rotation is dependent on the rotation of the input
> shaft
> > > and
> > > > > the difference in the number of teeth between the flex spline and
> the
> > > > > circular spline. The flex spline has fewer teeth than the circular
> > > spline,
> > > > > so it can rotate at a much reduced ratio and in the opposite
> direction
> > > than
> > > > > that of the input shaft. The reduction ration is given by: (number
> of
> > > flex
> > > > > spline teeth ? number of circular spline teeth) / number of flex
> spline
> > > > > teeth. So for example, if the flex spline has 100 teeth and the
> > > circular
> > > > > spline has 105, the reduction ratio is (100 ? 105) / 100 = -0.05
> which
> > > > > means that the flex spline ration is -5/100 (minus indicates the
> > > opposite
> > > > > direction of spin). The difference in the number of teeth can be
> > > changed to
> > > > > accommodate different reduction ratios and thus different
> specialized
> > > needs
> > > > > and requirements."
> > > > >
> > > > > So how many teeth have you on the fixed verses flex gear?  And did
> you
> > > by
> > > > > chance miscount?
> > >

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

In both cases the direction is the same?  Like in real life?

> -Original Message-
> From: Sam Sokolik [mailto:samco...@gmail.com]
> Sent: March-22-21 9:48 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> 
> Makes sense.. :)
> 
> On Mon, Mar 22, 2021 at 11:37 AM John Dammeyer 
> wrote:
> 
> > Using the math from that link below
> > (202-200)/200=0.01 ==> inverted is 100:1.
> >
> > Done the other way...  If that's possible then
> > (202-200)/202 = 0.0099009900... ==> inverted is 101:1
> >
> > John
> >
> > > -Original Message-
> > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > > Sent: March-22-21 6:19 AM
> > > To: Enhanced Machine Controller (EMC)
> > > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> > >
> > > 202,200 for the outside spline and the flex gear is 200.  In this
> > situation
> > > - the 202 tooth spline is stationary to the stepper.  The 200 tooth
> > outside
> > > spline is mounted to the faceplate.  In this layout - the ratio apears to
> > > be 101:1
> > >
> > > In this situation the stepper motor and the face plate spin the same
> > > direction.
> > >
> > > With the same set of outside spines swapped - the ratio is 100:1
> > >
> > > I am sure Andy can explain it.  It doesn't make sense to me.
> > >
> > > Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> > >
> > > sam
> > >
> > > On Mon, Mar 22, 2021 at 12:58 AM John Dammeyer 
> > > wrote:
> > >
> > > >
> > > >
> > > > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > > > > So.   interesting..   I just swapped the gears..  Before my
> > ratio was
> > > > > 100:1.   Input scale was 1600step/rev * 100 = 16/360 =
> > 444.444
> > > > > input scale.
> > > > >
> > > > > Now I reversed the outside splines.   I thought - wow - I must be
> > losing
> > > > > steps - but i would aways come back to zero.   Finally though -
> > maybe the
> > > > > ratio was now 102:1 - no.  over shot.
> > > > >
> > > > > so the final solution seems to be 101:1  WTH?
> > > > >
> > > > > sam
> > > >
> > > > Hi Sam,
> > > > I found this at:
> > > > https://www.engineeringclicks.com/harmonic-drive/
> > > >
> > > > "The rate of rotation is dependent on the rotation of the input shaft
> > and
> > > > the difference in the number of teeth between the flex spline and the
> > > > circular spline. The flex spline has fewer teeth than the circular
> > spline,
> > > > so it can rotate at a much reduced ratio and in the opposite direction
> > than
> > > > that of the input shaft. The reduction ration is given by: (number of
> > flex
> > > > spline teeth ? number of circular spline teeth) / number of flex spline
> > > > teeth. So for example, if the flex spline has 100 teeth and the
> > circular
> > > > spline has 105, the reduction ratio is (100 ? 105) / 100 = -0.05 which
> > > > means that the flex spline ration is -5/100 (minus indicates the
> > opposite
> > > > direction of spin). The difference in the number of teeth can be
> > changed to
> > > > accommodate different reduction ratios and thus different specialized
> > needs
> > > > and requirements."
> > > >
> > > > So how many teeth have you on the fixed verses flex gear?  And did you
> > by
> > > > chance miscount?
> > > > John Dammeyer
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > ___
> > > > Emc-users mailing list
> > > > Emc-users@lists.sourceforge.net
> > > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > > >
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> 
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

Makes sense.. :)

On Mon, Mar 22, 2021 at 11:37 AM John Dammeyer 
wrote:

> Using the math from that link below
> (202-200)/200=0.01 ==> inverted is 100:1.
>
> Done the other way...  If that's possible then
> (202-200)/202 = 0.0099009900... ==> inverted is 101:1
>
> John
>
> > -Original Message-
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > Sent: March-22-21 6:19 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> >
> > 202,200 for the outside spline and the flex gear is 200.  In this
> situation
> > - the 202 tooth spline is stationary to the stepper.  The 200 tooth
> outside
> > spline is mounted to the faceplate.  In this layout - the ratio apears to
> > be 101:1
> >
> > In this situation the stepper motor and the face plate spin the same
> > direction.
> >
> > With the same set of outside spines swapped - the ratio is 100:1
> >
> > I am sure Andy can explain it.  It doesn't make sense to me.
> >
> > Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> >
> > sam
> >
> > On Mon, Mar 22, 2021 at 12:58 AM John Dammeyer 
> > wrote:
> >
> > >
> > >
> > > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > > > So.   interesting..   I just swapped the gears..  Before my
> ratio was
> > > > 100:1.   Input scale was 1600step/rev * 100 = 16/360 =
> 444.444
> > > > input scale.
> > > >
> > > > Now I reversed the outside splines.   I thought - wow - I must be
> losing
> > > > steps - but i would aways come back to zero.   Finally though -
> maybe the
> > > > ratio was now 102:1 - no.  over shot.
> > > >
> > > > so the final solution seems to be 101:1  WTH?
> > > >
> > > > sam
> > >
> > > Hi Sam,
> > > I found this at:
> > > https://www.engineeringclicks.com/harmonic-drive/
> > >
> > > "The rate of rotation is dependent on the rotation of the input shaft
> and
> > > the difference in the number of teeth between the flex spline and the
> > > circular spline. The flex spline has fewer teeth than the circular
> spline,
> > > so it can rotate at a much reduced ratio and in the opposite direction
> than
> > > that of the input shaft. The reduction ration is given by: (number of
> flex
> > > spline teeth � number of circular spline teeth) / number of flex spline
> > > teeth. So for example, if the flex spline has 100 teeth and the
> circular
> > > spline has 105, the reduction ratio is (100 � 105) / 100 = -0.05 which
> > > means that the flex spline ration is -5/100 (minus indicates the
> opposite
> > > direction of spin). The difference in the number of teeth can be
> changed to
> > > accommodate different reduction ratios and thus different specialized
> needs
> > > and requirements."
> > >
> > > So how many teeth have you on the fixed verses flex gear?  And did you
> by
> > > chance miscount?
> > > John Dammeyer
> > >
> > >
> > >
> > >
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

Using the math from that link below 
(202-200)/200=0.01 ==> inverted is 100:1.

Done the other way...  If that's possible then
(202-200)/202 = 0.0099009900... ==> inverted is 101:1

John

> -Original Message-
> From: Sam Sokolik [mailto:samco...@gmail.com]
> Sent: March-22-21 6:19 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> 
> 202,200 for the outside spline and the flex gear is 200.  In this situation
> - the 202 tooth spline is stationary to the stepper.  The 200 tooth outside
> spline is mounted to the faceplate.  In this layout - the ratio apears to
> be 101:1
> 
> In this situation the stepper motor and the face plate spin the same
> direction.
> 
> With the same set of outside spines swapped - the ratio is 100:1
> 
> I am sure Andy can explain it.  It doesn't make sense to me.
> 
> Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
> 
> sam
> 
> On Mon, Mar 22, 2021 at 12:58 AM John Dammeyer 
> wrote:
> 
> >
> >
> > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > > So.   interesting..   I just swapped the gears..  Before my ratio was
> > > 100:1.   Input scale was 1600step/rev * 100 = 16/360 = 444.444
> > > input scale.
> > >
> > > Now I reversed the outside splines.   I thought - wow - I must be losing
> > > steps - but i would aways come back to zero.   Finally though - maybe the
> > > ratio was now 102:1 - no.  over shot.
> > >
> > > so the final solution seems to be 101:1  WTH?
> > >
> > > sam
> >
> > Hi Sam,
> > I found this at:
> > https://www.engineeringclicks.com/harmonic-drive/
> >
> > "The rate of rotation is dependent on the rotation of the input shaft and
> > the difference in the number of teeth between the flex spline and the
> > circular spline. The flex spline has fewer teeth than the circular spline,
> > so it can rotate at a much reduced ratio and in the opposite direction than
> > that of the input shaft. The reduction ration is given by: (number of flex
> > spline teeth � number of circular spline teeth) / number of flex spline
> > teeth. So for example, if the flex spline has 100 teeth and the circular
> > spline has 105, the reduction ratio is (100 � 105) / 100 = -0.05 which
> > means that the flex spline ration is -5/100 (minus indicates the opposite
> > direction of spin). The difference in the number of teeth can be changed to
> > accommodate different reduction ratios and thus different specialized needs
> > and requirements."
> >
> > So how many teeth have you on the fixed verses flex gear?  And did you by
> > chance miscount?
> > John Dammeyer
> >
> >
> >
> >
> >
> > ___
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> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> 
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 22 March 2021 09:19:19 Sam Sokolik wrote:

> 202,200 for the outside spline and the flex gear is 200.  In this
> situation - the 202 tooth spline is stationary to the stepper.  The
> 200 tooth outside spline is mounted to the faceplate.  In this layout
> - the ratio apears to be 101:1
>
> In this situation the stepper motor and the face plate spin the same
> direction.
>
Expected I think Sam. The difference in speeds is because the stationary 
gear is the reference. 202/200=1.01 but 200/202=0.9900990099, is not .99 
flat. The reciprocal's should match and do though.

But the rest of the proof is above my pay grade, the 8 years I did spend 
in school was blessed with a male math teacher far more interested in 
what was in the girls panties than in actually teaching math.

He eventually disappeared in the middle of the night, it was rumored at 
the insistance of a loaded 12 gauge held by an un-named girls father. I 
was out of town, working at a hardware store fixing tv's at the time. 
And driving the stores pickup on service calls sickly bird since I 
wasn't old enough to get a drivers license yet.

Small towns, pop 270 or so on Saturday nights, tend to solve such 
problems w/o involving the county sheriff. I heard about 4th hand, that 
he did get arrested for similar reasons a year or so later in another 
small town.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[andy pugh]

On Mon, 22 Mar 2021 at 13:23, Sam Sokolik  wrote:

> I am sure Andy can explain it.  It doesn't make sense to me.

It's because there is an extra 1-tooth movement of the spline with the
moving gear.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

wow - lets try that again...  Must be too early

202,200 for the outside spline and the flex gear is 200.  In this situation
- the 200 tooth spline is stationary to the stepper.  The 202 tooth outside
spline is mounted to the faceplate.  In this layout - the ratio apears to
be 101:1

In this situation the stepper motor and the face plate spin the same
direction.

With the same set of outside spines swapped - the ratio is 100:1

I am sure Andy can explain it.  It doesn't make sense to me.

Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ

sam


On Mon, Mar 22, 2021 at 8:19 AM Sam Sokolik  wrote:

> 202,200 for the outside spline and the flex gear is 200.  In this
> situation - the 202 tooth spline is stationary to the stepper.  The 200
> tooth outside spline is mounted to the faceplate.  In this layout - the
> ratio apears to be 101:1
>
> In this situation the stepper motor and the face plate spin the same
> direction.
>
> With the same set of outside spines swapped - the ratio is 100:1
>
> I am sure Andy can explain it.  It doesn't make sense to me.
>
> Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ
>
> sam
>
> On Mon, Mar 22, 2021 at 12:58 AM John Dammeyer 
> wrote:
>
>>
>>
>> > From: Sam Sokolik [mailto:samco...@gmail.com]
>> > So.   interesting..   I just swapped the gears..  Before my ratio
>> was
>> > 100:1.   Input scale was 1600step/rev * 100 = 16/360 = 444.444
>> > input scale.
>> >
>> > Now I reversed the outside splines.   I thought - wow - I must be losing
>> > steps - but i would aways come back to zero.   Finally though - maybe
>> the
>> > ratio was now 102:1 - no.  over shot.
>> >
>> > so the final solution seems to be 101:1  WTH?
>> >
>> > sam
>>
>> Hi Sam,
>> I found this at:
>> https://www.engineeringclicks.com/harmonic-drive/
>>
>> "The rate of rotation is dependent on the rotation of the input shaft and
>> the difference in the number of teeth between the flex spline and the
>> circular spline. The flex spline has fewer teeth than the circular spline,
>> so it can rotate at a much reduced ratio and in the opposite direction than
>> that of the input shaft. The reduction ration is given by: (number of flex
>> spline teeth – number of circular spline teeth) / number of flex spline
>> teeth. So for example, if the flex spline has 100 teeth and the circular
>> spline has 105, the reduction ratio is (100 – 105) / 100 = -0.05 which
>> means that the flex spline ration is -5/100 (minus indicates the opposite
>> direction of spin). The difference in the number of teeth can be changed to
>> accommodate different reduction ratios and thus different specialized needs
>> and requirements."
>>
>> So how many teeth have you on the fixed verses flex gear?  And did you by
>> chance miscount?
>> John Dammeyer
>>
>>
>>
>>
>>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

202,200 for the outside spline and the flex gear is 200.  In this situation
- the 202 tooth spline is stationary to the stepper.  The 200 tooth outside
spline is mounted to the faceplate.  In this layout - the ratio apears to
be 101:1

In this situation the stepper motor and the face plate spin the same
direction.

With the same set of outside spines swapped - the ratio is 100:1

I am sure Andy can explain it.  It doesn't make sense to me.

Happy with runout...  https://www.youtube.com/watch?v=eLyP2YwdstQ

sam

On Mon, Mar 22, 2021 at 12:58 AM John Dammeyer 
wrote:

>
>
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > So.   interesting..   I just swapped the gears..  Before my ratio was
> > 100:1.   Input scale was 1600step/rev * 100 = 16/360 = 444.444
> > input scale.
> >
> > Now I reversed the outside splines.   I thought - wow - I must be losing
> > steps - but i would aways come back to zero.   Finally though - maybe the
> > ratio was now 102:1 - no.  over shot.
> >
> > so the final solution seems to be 101:1  WTH?
> >
> > sam
>
> Hi Sam,
> I found this at:
> https://www.engineeringclicks.com/harmonic-drive/
>
> "The rate of rotation is dependent on the rotation of the input shaft and
> the difference in the number of teeth between the flex spline and the
> circular spline. The flex spline has fewer teeth than the circular spline,
> so it can rotate at a much reduced ratio and in the opposite direction than
> that of the input shaft. The reduction ration is given by: (number of flex
> spline teeth – number of circular spline teeth) / number of flex spline
> teeth. So for example, if the flex spline has 100 teeth and the circular
> spline has 105, the reduction ratio is (100 – 105) / 100 = -0.05 which
> means that the flex spline ration is -5/100 (minus indicates the opposite
> direction of spin). The difference in the number of teeth can be changed to
> accommodate different reduction ratios and thus different specialized needs
> and requirements."
>
> So how many teeth have you on the fixed verses flex gear?  And did you by
> chance miscount?
> John Dammeyer
>
>
>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

> From: Sam Sokolik [mailto:samco...@gmail.com]
> So.   interesting..   I just swapped the gears..  Before my ratio was
> 100:1.   Input scale was 1600step/rev * 100 = 16/360 = 444.444
> input scale.
> 
> Now I reversed the outside splines.   I thought - wow - I must be losing
> steps - but i would aways come back to zero.   Finally though - maybe the
> ratio was now 102:1 - no.  over shot.
> 
> so the final solution seems to be 101:1  WTH?
> 
> sam

Hi Sam,
I found this at:
https://www.engineeringclicks.com/harmonic-drive/

"The rate of rotation is dependent on the rotation of the input shaft and the 
difference in the number of teeth between the flex spline and the circular 
spline. The flex spline has fewer teeth than the circular spline, so it can 
rotate at a much reduced ratio and in the opposite direction than that of the 
input shaft. The reduction ration is given by: (number of flex spline teeth – 
number of circular spline teeth) / number of flex spline teeth. So for example, 
if the flex spline has 100 teeth and the circular spline has 105, the reduction 
ratio is (100 – 105) / 100 = -0.05 which means that the flex spline ration is 
-5/100 (minus indicates the opposite direction of spin). The difference in the 
number of teeth can be changed to accommodate different reduction ratios and 
thus different specialized needs and requirements."

So how many teeth have you on the fixed verses flex gear?  And did you by 
chance miscount?
John Dammeyer





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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

So.   interesting..   I just swapped the gears..  Before my ratio was
100:1.   Input scale was 1600step/rev * 100 = 16/360 = 444.444
input scale.

Now I reversed the outside splines.   I thought - wow - I must be losing
steps - but i would aways come back to zero.   Finally though - maybe the
ratio was now 102:1 - no.  over shot.

so the final solution seems to be 101:1  WTH?

sam

On Sun, Mar 21, 2021 at 4:15 PM andy pugh  wrote:

> On Sun, 21 Mar 2021 at 20:21, Viesturs Lācis 
> wrote:
>
> > I do not understand, how to get equal pitch diameter with different
> > number of teeth...
>
> You can shift the profile of gear teeth. You can add an extra couple
> of teeth, which moves more of the tooth above the pitch circle, or
> remove a couple and have less tooth above the pitch circle.
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[andy pugh]

On Sun, 21 Mar 2021 at 20:21, Viesturs Lācis  wrote:

> I do not understand, how to get equal pitch diameter with different
> number of teeth...

You can shift the profile of gear teeth. You can add an extra couple
of teeth, which moves more of the tooth above the pitch circle, or
remove a couple and have less tooth above the pitch circle.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Sunday 21 March 2021 16:16:59 Viesturs Lācis wrote:

> otrd., 2021. g. 26. janv., plkst. 19:26 — lietotājs andy pugh
>
> () rakstīja:
> > You have two internally toothed gears and a double-height
> > flex-spline. The gears have 202 and 200 teeth, the flex-spline has
> > 200.
> > That means that the flex-spline is static relative to the 200 tooth
> > gear, but moves the 202 tooth gear.
>
> My apologies if I missed it explained somewhere in this thread, but I
> have a question about the design of those two gears with internal
> teeth:
> If I understand correctly, pitch diameter is equal for both gears. But
> the number of teeth is different. IMHO it should affect the pitch of
> the teeth. Is that correct? Does it mean that there are 2 different
> rows of teeth on flexspline - for each of the internal teeth gears?
> There was a suggestion to use timing belt as flexspline, so that would
> mean that teeth pitch is equal on both internal teeth gears, but then
> I do not understand, how to get equal pitch diameter with different
> number of teeth...
>
> Viesturs
>
I don't think you can call me an expert on openscad but the only thing I 
changed to go from 60 to 62 was the incremental rotation I used the 
place the teeth, which are in fact triangles made from passing a $fr=3 
to the cylinder code, getting an equilateral triangle whose tips are the 
diameter passed to cylinder. The roots of the tooth overlap changes very 
slightly which changes the pitch diameter by a miniscule amount that I 
haven't tried to compensate for. There are at least 3 ways to go about 
assuring a consistent pitch diameter but that code is a bowl of noodle 
soup already. Ideally, the size of the cylinder that forms the tooth 
should change too, but my code doesn't do that. That would also change 
the inner circle diameter, but I jusr sized that to assure there weren't 
any floating parts of the tooth base where it sits on the inside face of 
the outer shell.

I hope that makes sense. Attached for your entertainment is the .scad 
that generates the outer rings, I switch tooth counts by having all 
three possibilities in there with 2 commented out. Don't bust a gut 
laughing at it... But it seems to work ok.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 
// new example, using a low ratio harmonic drive floating
// splined belt with 60 teeth.
// s/b 30/1 when finished.
$aa=69.000; // was 70. a blond one too big
$xx=9.75000;
$dd1=111.4000;
$dd0=120.;
$fx = ([ 360. / 60. ]); // arc of circle per tooth, works but...
// overall span of armature plus bearings equals 96.6mm's
$fr = [ 0.]; // establish its storage
echo ("10 ", $aa, $xx, $dd0, $dd1, $fr, $fx) ;  // echo? yes, once
difference() { // outside smoother, room for bolt holes
cylinder(d=$dd0, h=$xx, $fn=360); //outer is fussy
cylinder(d=$dd1, h=$xx, $fn=180); //but the inner isn't
}
// don't forget the bolt holes!!!
// for 6.0 we got 60 teeth, for 62 teeth inc is 5.8064516129
// those 60 teeth rendered at 3.69mm peak to valley
// use this "for" for 62 teeth
//for($fr=[ 0.: 5.8064516129  : 360. ]){ //can't pass $fd to 
this for, why?
//use this "for" for 60 teeth
for($fr=[ 0: 6.0  : 360 ]){  
//use this "for" for 58 teeth
//for($fr=[ 0 : 6.20689655172 : 360 ]){
//cylinder(h=11.75, d=8, center=true);

rotate([0., 0., $fr]) // works, finally
// this below works, but again, can't pass a var to translate
// what the hell???
// 
translate([54.0500, 0., 0.])  // mv x only
scale(v= [.100, .100, 1.00]) // might use a small xy
   // differential here to improve tooth fit.
rotate(180) // same here, using $var's doesn't work here or for
// cylinder. switch rotate on for outers and readjust sizes
cylinder(d=$aa, h=$xx, $fn=3); // make thick triangle
}; // switch h=9.500 for outer rings
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Viesturs Lācis]

otrd., 2021. g. 26. janv., plkst. 19:26 — lietotājs andy pugh
() rakstīja:
>
> You have two internally toothed gears and a double-height flex-spline.
> The gears have 202 and 200 teeth, the flex-spline has 200.
> That means that the flex-spline is static relative to the 200 tooth
> gear, but moves the 202 tooth gear.

My apologies if I missed it explained somewhere in this thread, but I
have a question about the design of those two gears with internal
teeth:
If I understand correctly, pitch diameter is equal for both gears. But
the number of teeth is different. IMHO it should affect the pitch of
the teeth. Is that correct? Does it mean that there are 2 different
rows of teeth on flexspline - for each of the internal teeth gears?
There was a suggestion to use timing belt as flexspline, so that would
mean that teeth pitch is equal on both internal teeth gears, but then
I do not understand, how to get equal pitch diameter with different
number of teeth...

Viesturs


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

I have a bolt hole pattern for a small 3 jaw we have.Still have to make
an alignment disk for it.

On Sun, Mar 21, 2021, 2:17 PM John Dammeyer  wrote:

> Does a chuck also fit onto that?
> Still trying to decide what to do with mine.
> John Dammeyer
>
> > -Original Message-
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > Sent: March-21-21 11:46 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
> >
> > On Sat, Mar 20, 2021 at 2:44 PM Gene Heskett 
> wrote:
> >
> > > On Saturday 20 March 2021 14:52:51 Sam Sokolik wrote:
> > >
> > > > Currently I am using Vaseline...  The black is plastic wear...
> > > >
> > > Humm, I've heard its not recommended, as it's petroleum based. I won't
> > > have that wear evidence though, this Dremel 3d45 came with clear PETG,
> > > and although I've two spools of it, one about used up now, when thats
> > > used up I'll install the 2nd, and I've some bright green PETG to rewind
> > > on the first of the special 3/4 kg spools this thing uses.
> > >
> > > These slightly smaller Dremel spools have RFID chips in them so they
> can
> > > tell the printer what its eating. At least enough to display it. But
> > > cura still runs the show.
> > >
> > > I have not carved any alu for a housing yet, next on the agenda here
> as I
> > > wanted a final size check from these innards first.
> > >
> > > I'd post a pix, clear stuff is wierd looking, but when I turned on the
> > > camera an hour back it yelped for a battery and died.
> > >
> > > And as a reloader, I have a couple oz of moly powder I may sprinkle a
> few
> > > grains of into a teaspoon of crisco just for S & G's. But with
> > > everything made from PETG, its surface is hard and polished, so the
> > > contact friction seems to be quite low anyway.  Nothing like PLA for
> > > friction.
> > >
> > > Thanks Sam S.
> > >
> > > Take care abd stay well now.
> > >
> > > [...]
> > >
> > > Cheers, Gene Heskett
> > > --
> > > "There are four boxes to be used in defense of liberty:
> > >  soap, ballot, jury, and ammo. Please use in that order."
> > > -Ed Howdershelt (Author)
> > > If we desire respect for the law, we must first make the law
> respectable.
> > >  - Louis D. Brandeis
> > > Genes Web page <http://geneslinuxbox.net:6309/gene>
> > >
> > >
> > > ___
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> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > >
> >
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>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

Does a chuck also fit onto that?
Still trying to decide what to do with mine.
John Dammeyer

> -Original Message-
> From: Sam Sokolik [mailto:samco...@gmail.com]
> Sent: March-21-21 11:46 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> 
> http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg
> 
> On Sat, Mar 20, 2021 at 2:44 PM Gene Heskett  wrote:
> 
> > On Saturday 20 March 2021 14:52:51 Sam Sokolik wrote:
> >
> > > Currently I am using Vaseline...  The black is plastic wear...
> > >
> > Humm, I've heard its not recommended, as it's petroleum based. I won't
> > have that wear evidence though, this Dremel 3d45 came with clear PETG,
> > and although I've two spools of it, one about used up now, when thats
> > used up I'll install the 2nd, and I've some bright green PETG to rewind
> > on the first of the special 3/4 kg spools this thing uses.
> >
> > These slightly smaller Dremel spools have RFID chips in them so they can
> > tell the printer what its eating. At least enough to display it. But
> > cura still runs the show.
> >
> > I have not carved any alu for a housing yet, next on the agenda here as I
> > wanted a final size check from these innards first.
> >
> > I'd post a pix, clear stuff is wierd looking, but when I turned on the
> > camera an hour back it yelped for a battery and died.
> >
> > And as a reloader, I have a couple oz of moly powder I may sprinkle a few
> > grains of into a teaspoon of crisco just for S & G's. But with
> > everything made from PETG, its surface is hard and polished, so the
> > contact friction seems to be quite low anyway.  Nothing like PLA for
> > friction.
> >
> > Thanks Sam S.
> >
> > Take care abd stay well now.
> >
> > [...]
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > If we desire respect for the law, we must first make the law respectable.
> >  - Louis D. Brandeis
> > Genes Web page <http://geneslinuxbox.net:6309/gene>
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> 
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

http://electronicsam.com/images/greenmachine/IMG_20210321_133551.jpg

On Sat, Mar 20, 2021 at 2:44 PM Gene Heskett  wrote:

> On Saturday 20 March 2021 14:52:51 Sam Sokolik wrote:
>
> > Currently I am using Vaseline...  The black is plastic wear...
> >
> Humm, I've heard its not recommended, as it's petroleum based. I won't
> have that wear evidence though, this Dremel 3d45 came with clear PETG,
> and although I've two spools of it, one about used up now, when thats
> used up I'll install the 2nd, and I've some bright green PETG to rewind
> on the first of the special 3/4 kg spools this thing uses.
>
> These slightly smaller Dremel spools have RFID chips in them so they can
> tell the printer what its eating. At least enough to display it. But
> cura still runs the show.
>
> I have not carved any alu for a housing yet, next on the agenda here as I
> wanted a final size check from these innards first.
>
> I'd post a pix, clear stuff is wierd looking, but when I turned on the
> camera an hour back it yelped for a battery and died.
>
> And as a reloader, I have a couple oz of moly powder I may sprinkle a few
> grains of into a teaspoon of crisco just for S & G's. But with
> everything made from PETG, its surface is hard and polished, so the
> contact friction seems to be quite low anyway.  Nothing like PLA for
> friction.
>
> Thanks Sam S.
>
> Take care abd stay well now.
>
> [...]
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
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>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Saturday 20 March 2021 14:52:51 Sam Sokolik wrote:

> Currently I am using Vaseline...  The black is plastic wear...
>
Humm, I've heard its not recommended, as it's petroleum based. I won't 
have that wear evidence though, this Dremel 3d45 came with clear PETG, 
and although I've two spools of it, one about used up now, when thats 
used up I'll install the 2nd, and I've some bright green PETG to rewind 
on the first of the special 3/4 kg spools this thing uses.

These slightly smaller Dremel spools have RFID chips in them so they can 
tell the printer what its eating. At least enough to display it. But 
cura still runs the show.

I have not carved any alu for a housing yet, next on the agenda here as I 
wanted a final size check from these innards first.

I'd post a pix, clear stuff is wierd looking, but when I turned on the 
camera an hour back it yelped for a battery and died.

And as a reloader, I have a couple oz of moly powder I may sprinkle a few 
grains of into a teaspoon of crisco just for S & G's. But with 
everything made from PETG, its surface is hard and polished, so the 
contact friction seems to be quite low anyway.  Nothing like PLA for 
friction.

Thanks Sam S.

Take care abd stay well now.

[...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

Currently I am using Vaseline...  The black is plastic wear...

On Sat, Mar 20, 2021, 1:43 PM Gene Heskett  wrote:

> On Saturday 20 March 2021 09:57:11 Sam Sokolik wrote:
>
> > 36 hours - For this purpose I think we are good.
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210320_072206.jpg
> >
> > Next I think a destructive torque test and then maybe some actual
> > cutting...  I need to finish the face plate first though.
>
> Looking pretty good Sam, but the color of the lube I can see makes me
> want the recipe.
>
> FWIW, some of the first failure may be from the UNK lube migrating out of
> those huge bearings, this stuff is known to do strange things when
> exposed to petroleum based Lubes, even if just the fumes. I've seen and
> used the vegetbale grease sold as crisco and gotten away with it for
> limited time.
>
> That has the looks of something with moly or graphite in it?
>
> Can you share that info?
>
> Thank you Sam S.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Saturday 20 March 2021 09:57:11 Sam Sokolik wrote:

> 36 hours - For this purpose I think we are good.
>
> http://electronicsam.com/images/greenmachine/IMG_20210320_072206.jpg
>
> Next I think a destructive torque test and then maybe some actual
> cutting...  I need to finish the face plate first though.

Looking pretty good Sam, but the color of the lube I can see makes me 
want the recipe.

FWIW, some of the first failure may be from the UNK lube migrating out of 
those huge bearings, this stuff is known to do strange things when 
exposed to petroleum based Lubes, even if just the fumes. I've seen and 
used the vegetbale grease sold as crisco and gotten away with it for 
limited time.

That has the looks of something with moly or graphite in it?

Can you share that info?

Thank you Sam S.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

36 hours - For this purpose I think we are good.

http://electronicsam.com/images/greenmachine/IMG_20210320_072206.jpg

Next I think a destructive torque test and then maybe some actual
cutting...  I need to finish the face plate first though.

On Fri, Mar 19, 2021 at 11:16 PM Chris Albertson 
wrote:

> If you wanted a more durable part, you can send the STL file out to a
> service that prints it in stainless steel.  You might change the design to
> reduce the bulk because they charge by the gram for the steel.
>
> SpaceX is printing pre-burner parts for their new Raptor engines.  If
> anything needs to be durable it is rocket engine parts.  I've read about
> turbine engine blade retainers being printed in Inconel too.   It is not so
> expensive if you think to reduce the weight of the parts.
>
> On Fri, Mar 19, 2021 at 5:10 PM Gregg Eshelman via Emc-users <
> emc-users@lists.sourceforge.net> wrote:
>
> > 3D printing fixtures to hold things you've 3D printed can be done the
> same
> > way. Put two cubes side by side with a bit of gap between. Position the
> > object at the divide so that it's half embedded in each cube, with no
> > undercuts. Subtract the object from both cubes. Print the cubes and you
> > have blocks to clamp in a vise to hold the object for more operations
> like
> > drilling, tapping, pressing in threaded inserts etc.
> >
> >
> > On Friday, March 19, 2021, 10:53:55 AM MDT, Chris Albertson <
> > albertson.ch...@gmail.com> wrote:
> >
> >  When I first saw this, my idea was to print the internal tooth gear
> > "backward" as a mold that makes up the central space in the aluminum
> > housing, then pour in an epoxy/glass composite paste.
> >
> > I've seen this done on other projects, the most complex is a prosthetic
> > hand I'm slowly working on.  The designer made the "finger bone" in 3D
> > printed plastic, then you put it inside a hollow 3D printed mold and pour
> > in polyurethane resin which "over-molds" the plastic core.  It makes a
> > very tough non-slip fingerpad.Seeing this got me thinking about what
> I
> > call "hybrid design" what you combine 3D printing with metal and resin
> > casting.  It sounds complex but if you have a 3D CAD system and a printer
> > mold-making is nearly trivial, Use the part you want to make and subtract
> > that from the inside of a brick.
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

If you wanted a more durable part, you can send the STL file out to a
service that prints it in stainless steel.  You might change the design to
reduce the bulk because they charge by the gram for the steel.

SpaceX is printing pre-burner parts for their new Raptor engines.  If
anything needs to be durable it is rocket engine parts.  I've read about
turbine engine blade retainers being printed in Inconel too.   It is not so
expensive if you think to reduce the weight of the parts.

On Fri, Mar 19, 2021 at 5:10 PM Gregg Eshelman via Emc-users <
emc-users@lists.sourceforge.net> wrote:

> 3D printing fixtures to hold things you've 3D printed can be done the same
> way. Put two cubes side by side with a bit of gap between. Position the
> object at the divide so that it's half embedded in each cube, with no
> undercuts. Subtract the object from both cubes. Print the cubes and you
> have blocks to clamp in a vise to hold the object for more operations like
> drilling, tapping, pressing in threaded inserts etc.
>
>
> On Friday, March 19, 2021, 10:53:55 AM MDT, Chris Albertson <
> albertson.ch...@gmail.com> wrote:
>
>  When I first saw this, my idea was to print the internal tooth gear
> "backward" as a mold that makes up the central space in the aluminum
> housing, then pour in an epoxy/glass composite paste.
>
> I've seen this done on other projects, the most complex is a prosthetic
> hand I'm slowly working on.  The designer made the "finger bone" in 3D
> printed plastic, then you put it inside a hollow 3D printed mold and pour
> in polyurethane resin which "over-molds" the plastic core.  It makes a
> very tough non-slip fingerpad.Seeing this got me thinking about what I
> call "hybrid design" what you combine 3D printing with metal and resin
> casting.  It sounds complex but if you have a 3D CAD system and a printer
> mold-making is nearly trivial, Use the part you want to make and subtract
> that from the inside of a brick.
> ___
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> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gregg Eshelman via Emc-users]

3D printing fixtures to hold things you've 3D printed can be done the same way. 
Put two cubes side by side with a bit of gap between. Position the object at 
the divide so that it's half embedded in each cube, with no undercuts. Subtract 
the object from both cubes. Print the cubes and you have blocks to clamp in a 
vise to hold the object for more operations like drilling, tapping, pressing in 
threaded inserts etc.
 

On Friday, March 19, 2021, 10:53:55 AM MDT, Chris Albertson 
 wrote:  
 
 When I first saw this, my idea was to print the internal tooth gear
"backward" as a mold that makes up the central space in the aluminum
housing, then pour in an epoxy/glass composite paste.

I've seen this done on other projects, the most complex is a prosthetic
hand I'm slowly working on.  The designer made the "finger bone" in 3D
printed plastic, then you put it inside a hollow 3D printed mold and pour
in polyurethane resin which "over-molds" the plastic core.  It makes a
very tough non-slip fingerpad.    Seeing this got me thinking about what I
call "hybrid design" what you combine 3D printing with metal and resin
casting.  It sounds complex but if you have a 3D CAD system and a printer
mold-making is nearly trivial, Use the part you want to make and subtract
that from the inside of a brick.  
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Friday 19 March 2021 15:21:05 Sam Sokolik wrote:

> still running 18+ hours.

Sounds better Sam.

> On Fri, Mar 19, 2021 at 2:03 PM Gene Heskett  
wrote:
> > On Friday 19 March 2021 13:07:58 Sam Sokolik wrote:
> > > I think you want it as hard as you can that still last a decent
> > > amount of time..   Too rubbery and there will be more toque
> > > flex...
> >
> > Yes, it folds up and a nema 17 then makes sausage out of it.
> > [...]
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > If we desire respect for the law, we must first make the law
> > respectable. - Louis D. Brandeis
> > Genes Web page 
> >
> >
> > ___
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> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

still running 18+ hours.

On Fri, Mar 19, 2021 at 2:03 PM Gene Heskett  wrote:

> On Friday 19 March 2021 13:07:58 Sam Sokolik wrote:
>
> > I think you want it as hard as you can that still last a decent amount
> > of time..   Too rubbery and there will be more toque flex...
> >
> Yes, it folds up and a nema 17 then makes sausage out of it.
> [...]
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Friday 19 March 2021 13:07:58 Sam Sokolik wrote:

> I think you want it as hard as you can that still last a decent amount
> of time..   Too rubbery and there will be more toque flex...
>
Yes, it folds up and a nema 17 then makes sausage out of it.
[...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Friday 19 March 2021 12:53:40 John Dammeyer wrote:

> There are some other printable filaments that are far more flexible. 
> More like rubber.  Would perhaps that material work better?
>
I tried TPU in a previous failure but it was too soft, PETG outlasted it 
by 20/1. It also has a high sliding surface friction that can make it 
fold and buckle long before a 84oz/in nema17 runs out of torque, and 
swimming in crisco doesn't appear to help. PETG runs better dry than TPU 
wet the with Crisco. 

Take care All.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Friday 19 March 2021 12:51:55 Chris Albertson wrote:

> When I first saw this, my idea was to print the internal tooth gear
> "backward" as a mold that makes up the central space in the aluminum
> housing, then pour in an epoxy/glass composite paste.
>
> I've seen this done on other projects, the most complex is a
> prosthetic hand I'm slowly working on.  The designer made the "finger
> bone" in 3D printed plastic, then you put it inside a hollow 3D
> printed mold and pour in polyurethane resin which "over-molds" the
> plastic core.  It makes a very tough non-slip fingerpad.Seeing
> this got me thinking about what I call "hybrid design" what you
> combine 3D printing with metal and resin casting.   It sounds complex
> but if you have a 3D CAD system and a printer mold-making is nearly
> trivial, Use the part you want to make and subtract that from the
> inside of a brick.

Since I have a printer (Dremel 3D45) big enough to do it, I'm doing the 4 
internal pieces of it, in PETG, but will make an alu housing in 2 parts 
from 1" stock. But I'm learning OpenSCAD as I go and for my old wet ram, 
that is a slow slog. But it keeps me out of the bars too. :) Pix if and 
when I get it working.

 > On Fri, Mar 19, 2021 at 8:07 AM Sam Sokolik  
wrote:
> > So - this didn't make it 6 hours with the steppers running 833rpm
> > (3000deg/min at the face plate)  (forward reverse some
> > positioning...)
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210317_073558.jpg
> >
> > Now - I am sure it would last longer if it was run slower...  The
> > flex gear now has the consistency of chocolate..  It just crumbles.
> >
> > So - I printed the flex gear out of petg.   As of this morning it
> > has run for 12 hours and still positions correctly.  I would say -
> > if it last a good 24 hours - it will be perfect for a hobby 4th
> > axis.  It isn't going to be run like this in normal situations and
> > you can always print more gears...
> >
> > sam
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Friday 19 March 2021 11:03:05 Sam Sokolik wrote:

> So - this didn't make it 6 hours with the steppers running 833rpm
> (3000deg/min at the face plate)  (forward reverse some positioning...)
>
> http://electronicsam.com/images/greenmachine/IMG_20210317_073558.jpg
>
> Now - I am sure it would last longer if it was run slower...  The flex
> gear now has the consistency of chocolate..  It just crumbles.
>
> So - I printed the flex gear out of petg.   As of this morning it has
> run for 12 hours and still positions correctly.  I would say - if it
> last a good 24 hours - it will be perfect for a hobby 4th axis.  It
> isn't going to be run like this in normal situations and you can
> always print more gears...
>
> sam

I'm way behind you, but I am working in PETG too.  I thought about the 
thickness of the liner that makes the loose belt smooth on the inside, 
and I've made several, still looking for the size match that makes it 
all work RIGHT. But my thinking is that it should be thinner just to 
give it a greater flexability life.  And I'm using smaller bearings, 
mainly because I had a roll of them from a previously aborted attempt to 
use a conventional flex gear.  And I've been reworking my openscad files 
to make it closer and closer to pure parametric. I'll have to admit that 
this is putting a strain on my already damaged wet ram by the pulmonary 
embolism 7 years ago. That and openscad is a segfaulter about 2x a day 
are making it a bit of a headache. But I am learning, at least about 
openscad.

Thanks for posting the video, Sam. Stay safe and well.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

I think you want it as hard as you can that still last a decent amount of
time..   Too rubbery and there will be more toque flex...

On Fri, Mar 19, 2021, 11:58 AM John Dammeyer  wrote:

>
> There are some other printable filaments that are far more flexible.  More
> like rubber.  Would perhaps that material work better?
>
> John
>
> > -Original Message-
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> > Sent: March-19-21 8:03 AM
> > To: Enhanced Machine Controller (EMC)
> > Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> >
> > So - this didn't make it 6 hours with the steppers running 833rpm
> > (3000deg/min at the face plate)  (forward reverse some positioning...)
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210317_073558.jpg
> >
> > Now - I am sure it would last longer if it was run slower...  The flex
> gear
> > now has the consistency of chocolate..  It just crumbles.
> >
> > So - I printed the flex gear out of petg.   As of this morning it has run
> > for 12 hours and still positions correctly.  I would say - if it last a
> > good 24 hours - it will be perfect for a hobby 4th axis.  It isn't going
> to
> > be run like this in normal situations and you can always print more
> gears...
> >
> > sam
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

> From: andy pugh [mailto:bodge...@gmail.com]
> On Fri, 19 Mar 2021 at 15:07, Sam Sokolik  wrote:
> >
> > It isn't going to
> > be run like this in normal situations and you can always print more gears...
> 
> I wouldn't imagine that printing a new flex gear talkies very long, either?
> 
> --
> atp

As soon as one is printed you start the printer and make a spare.  (or 2 or 3). 
John




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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

Exactly...

On Fri, Mar 19, 2021, 11:58 AM andy pugh  wrote:

> On Fri, 19 Mar 2021 at 15:07, Sam Sokolik  wrote:
> >
> > It isn't going to
> > be run like this in normal situations and you can always print more
> gears...
>
> I wouldn't imagine that printing a new flex gear talkies very long, either?
>
> --
> atp
> "A motorcycle is a bicycle with a pandemonium attachment and is
> designed for the especial use of mechanical geniuses, daredevils and
> lunatics."
> — George Fitch, Atlanta Constitution Newspaper, 1912
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[andy pugh]

On Fri, 19 Mar 2021 at 15:07, Sam Sokolik  wrote:
>
> It isn't going to
> be run like this in normal situations and you can always print more gears...

I wouldn't imagine that printing a new flex gear talkies very long, either?

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

There are some other printable filaments that are far more flexible.  More like 
rubber.  Would perhaps that material work better?

John

> -Original Message-
> From: Sam Sokolik [mailto:samco...@gmail.com]
> Sent: March-19-21 8:03 AM
> To: Enhanced Machine Controller (EMC)
> Subject: Re: [Emc-users] Maybe a minimally printed harmonic drive?
> 
> So - this didn't make it 6 hours with the steppers running 833rpm
> (3000deg/min at the face plate)  (forward reverse some positioning...)
> 
> http://electronicsam.com/images/greenmachine/IMG_20210317_073558.jpg
> 
> Now - I am sure it would last longer if it was run slower...  The flex gear
> now has the consistency of chocolate..  It just crumbles.
> 
> So - I printed the flex gear out of petg.   As of this morning it has run
> for 12 hours and still positions correctly.  I would say - if it last a
> good 24 hours - it will be perfect for a hobby 4th axis.  It isn't going to
> be run like this in normal situations and you can always print more gears...
> 
> sam
> 
> ___
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

When I first saw this, my idea was to print the internal tooth gear
"backward" as a mold that makes up the central space in the aluminum
housing, then pour in an epoxy/glass composite paste.

I've seen this done on other projects, the most complex is a prosthetic
hand I'm slowly working on.  The designer made the "finger bone" in 3D
printed plastic, then you put it inside a hollow 3D printed mold and pour
in polyurethane resin which "over-molds" the plastic core.  It makes a
very tough non-slip fingerpad.Seeing this got me thinking about what I
call "hybrid design" what you combine 3D printing with metal and resin
casting.   It sounds complex but if you have a 3D CAD system and a printer
mold-making is nearly trivial, Use the part you want to make and subtract
that from the inside of a brick.

On Fri, Mar 19, 2021 at 8:07 AM Sam Sokolik  wrote:

> So - this didn't make it 6 hours with the steppers running 833rpm
> (3000deg/min at the face plate)  (forward reverse some positioning...)
>
> http://electronicsam.com/images/greenmachine/IMG_20210317_073558.jpg
>
> Now - I am sure it would last longer if it was run slower...  The flex gear
> now has the consistency of chocolate..  It just crumbles.
>
> So - I printed the flex gear out of petg.   As of this morning it has run
> for 12 hours and still positions correctly.  I would say - if it last a
> good 24 hours - it will be perfect for a hobby 4th axis.  It isn't going to
> be run like this in normal situations and you can always print more
> gears...
>
> sam
>
> ___
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-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

So - this didn't make it 6 hours with the steppers running 833rpm
(3000deg/min at the face plate)  (forward reverse some positioning...)

http://electronicsam.com/images/greenmachine/IMG_20210317_073558.jpg

Now - I am sure it would last longer if it was run slower...  The flex gear
now has the consistency of chocolate..  It just crumbles.

So - I printed the flex gear out of petg.   As of this morning it has run
for 12 hours and still positions correctly.  I would say - if it last a
good 24 hours - it will be perfect for a hobby 4th axis.  It isn't going to
be run like this in normal situations and you can always print more gears...

sam

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Monday 15 March 2021 00:08:00 Sam Sokolik wrote:

> another painful video
>
> https://www.youtube.com/watch?v=U3e83H2mEyk

I would like to see it go clear around and back to zero. That lack of 
backlash is, IMO, very very impressive.

You got me going on one with a 30/1 ratio, about done with the answer to 
my question as I am also making a 58 tooth just to see it it has room 
for that much moton.  That would make it go 4 teeth per turn, if it will 
fit for the stationary gear.  First plastic from my 3d45 cleans up 
fairly well, and I've not made provisions for bolts yet as I intend to 
cut recesses in 2 face pieces of 1" thick alu, to fit the smooth outer 
rings and goop the stationary ring into the recess.  I will make a 
larger recess in the output side, with a 3d printed output cup that will 
fit the output ring with goop. With splines this big, I suspect the 
elcheapo roller skate bearings will do for the flex stretcher, as it 
looks like a larger bearing is going to result in more tooth to tooth 
drag, using two stacked, one on each side of the disk.

Speed of course is relative, this dremel printer is about 35% slower than 
cura's estimates.  Fun, and educational since this is being done in 
openscad. And I'm still got a long ways to go to be an openscad guru, if 
ever. Variable "scope" is I think being a problem. :(

> On Sat, Mar 13, 2021 at 8:40 PM Sam Sokolik  wrote:
> > Getting closer... I have to drill a bunch of holes in the face
> > plate... also have to preload the wheel bearing (grind a bit from
> > the center)
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210313_201227.jpg


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[John Dammeyer]

> From: Sam Sokolik [mailto:samco...@gmail.com]
> 
> another painful video
> 
> https://www.youtube.com/watch?v=U3e83H2mEyk
> 
> On Sat, Mar 13, 2021 at 8:40 PM Sam Sokolik  wrote:
> 
> > Getting closer... I have to drill a bunch of holes in the face plate...
> > also have to preload the wheel bearing (grind a bit from the center)
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210313_201227.jpg
> >

Really enjoying these. 
John Dammeyer



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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

another painful video

https://www.youtube.com/watch?v=U3e83H2mEyk

On Sat, Mar 13, 2021 at 8:40 PM Sam Sokolik  wrote:

> Getting closer... I have to drill a bunch of holes in the face plate...
> also have to preload the wheel bearing (grind a bit from the center)
>
> http://electronicsam.com/images/greenmachine/IMG_20210313_201227.jpg
>
> On Fri, Mar 12, 2021 at 10:41 AM Gene Heskett 
> wrote:
>
>> On Wednesday 10 March 2021 12:58:08 John Dammeyer wrote:
>>
>> > Hi Sam,
>> > I found by making the wall thickness bigger along with the hole
>> > smaller and hub larger I was able to mount the hub on the lathe and
>> > bore both the bore and the outer part of the hub on the lathe to make
>> > them symmetrical.  That reduced a lot of wobble compared to earlier
>> > versions.
>> >
>> > In hindsight I would also have made some sort of holder that allowed
>> > me to skim the inside of the actually pulley part.  Instead I used
>> > sandpaper because as you can see it has the same roughness from the 3D
>> > printer as your toothed belt section has.
>> >
>> > The hub was a smooth press fit (by hand) in and out of the pulley
>> > part.  The photo showing it mounted still has the yellow pulley that
>> > had too small of a hub and the pressure from the set screw cracked it.
>> >  So the new green one has a wider set screw area.
>> >
>> > I suspect the biggest issue with your flex pulley would be holding it
>> > stable enough so you could skim away material.  Might even be best to
>> > print it with a flat face to hold it round.  Then mount it in a
>> > holder, skim the inside surface and then cut through the face at the
>> > back.  The flat face could even have mounting holes to mount onto the
>> > back of your plate.  This would keep it from turning in the mount
>> > while you skim it.
>> >
>> I've got a better idea, since LCNC can do a taper, taper the holder 2
>> thou, drive it all the way in so its gripped good, bore it to half that
>> taper, pull it out, turn the other face and repeat w/o touching the x
>> dial. Just make sure all the burrs on the teeth from the printer are
>> well cleaned off with a fresh blade in a box knife. Burrs will show as
>> wibbles in the bore if you dont. :(
>>
>> > John
>> >
>> > > From: Sam Sokolik [mailto:samco...@gmail.com]
>> > >
>> > > another update - at 1/2 step - the discrete resolution should be
>> > > about 40,000 divisions per rotation.  .009 deg.
>> > >
>> > > https://www.youtube.com/watch?v=IdfKre6zpEY
>> > >
>> > > On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik 
>> wrote:
>> > > > https://www.youtube.com/watch?v=ZVVffljc7kE
>>
>>
>> Cheers, Gene Heskett
>> --
>> "There are four boxes to be used in defense of liberty:
>>  soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author)
>> If we desire respect for the law, we must first make the law respectable.
>>  - Louis D. Brandeis
>> Genes Web page 
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

Getting closer... I have to drill a bunch of holes in the face plate...
also have to preload the wheel bearing (grind a bit from the center)

http://electronicsam.com/images/greenmachine/IMG_20210313_201227.jpg

On Fri, Mar 12, 2021 at 10:41 AM Gene Heskett  wrote:

> On Wednesday 10 March 2021 12:58:08 John Dammeyer wrote:
>
> > Hi Sam,
> > I found by making the wall thickness bigger along with the hole
> > smaller and hub larger I was able to mount the hub on the lathe and
> > bore both the bore and the outer part of the hub on the lathe to make
> > them symmetrical.  That reduced a lot of wobble compared to earlier
> > versions.
> >
> > In hindsight I would also have made some sort of holder that allowed
> > me to skim the inside of the actually pulley part.  Instead I used
> > sandpaper because as you can see it has the same roughness from the 3D
> > printer as your toothed belt section has.
> >
> > The hub was a smooth press fit (by hand) in and out of the pulley
> > part.  The photo showing it mounted still has the yellow pulley that
> > had too small of a hub and the pressure from the set screw cracked it.
> >  So the new green one has a wider set screw area.
> >
> > I suspect the biggest issue with your flex pulley would be holding it
> > stable enough so you could skim away material.  Might even be best to
> > print it with a flat face to hold it round.  Then mount it in a
> > holder, skim the inside surface and then cut through the face at the
> > back.  The flat face could even have mounting holes to mount onto the
> > back of your plate.  This would keep it from turning in the mount
> > while you skim it.
> >
> I've got a better idea, since LCNC can do a taper, taper the holder 2
> thou, drive it all the way in so its gripped good, bore it to half that
> taper, pull it out, turn the other face and repeat w/o touching the x
> dial. Just make sure all the burrs on the teeth from the printer are
> well cleaned off with a fresh blade in a box knife. Burrs will show as
> wibbles in the bore if you dont. :(
>
> > John
> >
> > > From: Sam Sokolik [mailto:samco...@gmail.com]
> > >
> > > another update - at 1/2 step - the discrete resolution should be
> > > about 40,000 divisions per rotation.  .009 deg.
> > >
> > > https://www.youtube.com/watch?v=IdfKre6zpEY
> > >
> > > On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik 
> wrote:
> > > > https://www.youtube.com/watch?v=ZVVffljc7kE
>
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
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>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Wednesday 10 March 2021 12:58:08 John Dammeyer wrote:

> Hi Sam,
> I found by making the wall thickness bigger along with the hole
> smaller and hub larger I was able to mount the hub on the lathe and
> bore both the bore and the outer part of the hub on the lathe to make
> them symmetrical.  That reduced a lot of wobble compared to earlier
> versions.
>
> In hindsight I would also have made some sort of holder that allowed
> me to skim the inside of the actually pulley part.  Instead I used
> sandpaper because as you can see it has the same roughness from the 3D
> printer as your toothed belt section has.
>
> The hub was a smooth press fit (by hand) in and out of the pulley
> part.  The photo showing it mounted still has the yellow pulley that
> had too small of a hub and the pressure from the set screw cracked it.
>  So the new green one has a wider set screw area.
>
> I suspect the biggest issue with your flex pulley would be holding it
> stable enough so you could skim away material.  Might even be best to
> print it with a flat face to hold it round.  Then mount it in a
> holder, skim the inside surface and then cut through the face at the
> back.  The flat face could even have mounting holes to mount onto the
> back of your plate.  This would keep it from turning in the mount
> while you skim it.
>
I've got a better idea, since LCNC can do a taper, taper the holder 2 
thou, drive it all the way in so its gripped good, bore it to half that 
taper, pull it out, turn the other face and repeat w/o touching the x 
dial. Just make sure all the burrs on the teeth from the printer are 
well cleaned off with a fresh blade in a box knife. Burrs will show as 
wibbles in the bore if you dont. :(

> John
>
> > From: Sam Sokolik [mailto:samco...@gmail.com]
> >
> > another update - at 1/2 step - the discrete resolution should be
> > about 40,000 divisions per rotation.  .009 deg.
> >
> > https://www.youtube.com/watch?v=IdfKre6zpEY
> >
> > On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik  
wrote:
> > > https://www.youtube.com/watch?v=ZVVffljc7kE


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Wednesday 10 March 2021 12:58:08 John Dammeyer wrote:

> Hi Sam,
> I found by making the wall thickness bigger along with the hole
> smaller and hub larger I was able to mount the hub on the lathe and
> bore both the bore and the outer part of the hub on the lathe to make
> them symmetrical.  That reduced a lot of wobble compared to earlier
> versions.
>
> In hindsight I would also have made some sort of holder that allowed
> me to skim the inside of the actually pulley part.  Instead I used
> sandpaper because as you can see it has the same roughness from the 3D
> printer as your toothed belt section has.
>
> The hub was a smooth press fit (by hand) in and out of the pulley
> part.  The photo showing it mounted still has the yellow pulley that
> had too small of a hub and the pressure from the set screw cracked it.
>  So the new green one has a wider set screw area.
>
> I suspect the biggest issue with your flex pulley would be holding it
> stable enough so you could skim away material.  Might even be best to
> print it with a flat face to hold it round.  Then mount it in a
> holder, skim the inside surface and then cut through the face at the
> back.  The flat face could even have mounting holes to mount onto the
> back of your plate.  This would keep it from turning in the mount
> while you skim it.
>
> John
>
Hi you two;

I've manage to beat openscad into enough submission to make the loose 
belt, approx 99mm at pitch diameter. With 60 "teeth" which are actually 
from equalateral triangles.  Now I've turned the triangles 180 degree so 
they face inward and increased the pitch radius to 54.5, and now making 
a 62 tooth outer ring for fit testing. But it occurs to me since I need 
a lessor gear ratio than 30/1, that I might be able to cheat a bit on 
the output ring, and get half the gear ratio and twice the speed if I 
made the the output ring with 58 teeth. I'm obviusly way behind you two, 
but before I waste a $30 roll of PETG, I thought I'd throw it out there 
for target practice by more experienced people.

Discuss? Tell me I'm out of my mind, your choice. :)



> > From: Sam Sokolik [mailto:samco...@gmail.com]
> >
> > another update - at 1/2 step - the discrete resolution should be
> > about 40,000 divisions per rotation.  .009 deg.
> >
> > https://www.youtube.com/watch?v=IdfKre6zpEY
> >
> > On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik  
wrote:
> > > https://www.youtube.com/watch?v=ZVVffljc7kE


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

If this thing works decent enough - I could easily then 'shape' the outside
gears. pretty easy...

sam

On Wed, Mar 10, 2021 at 2:00 PM Chris Albertson 
wrote:

> I've done this a few times.  PVA is best used if the mold is new.  You can
> spray in on the mold using an old spray bottle that used to hold kitchen
> and bath spray cleaner that is well rinsed out.  But after the mold is used
> a few times mould release wax alone is OK.The PVA has some tiny film
> thickness and a slight irregular surface and can't be polished.  Wax on the
> other hand can be buffed and made to shine.   The part is only as nicely
> finished as the mould.   Mould seem to get earlier to release with repeated
> use.  PVA dissolves in water, so you can soak the mould and part to release
> it.
>
> But it just might be that epoxy does not adhere to rubber and no release
> agent is needed.   We never used a release agent on latex rubber moulds.
>
> Carbon fibre parts have this high-tech mystique around them but they can be
> made with very crude and low-cost methods using just paper cups,
> popsicle sticks and c-clamps.
>
> You can buy one yard of carbon cloth for about $10 and it is a lifetime
> supply. Then cut it on bias into 1/8th inch strips and stir the strip until
> they become 1/8th inch long unwoven fibers, (or for more money buy "chopped
> carbon fiber") mix with epoxy to make a fibrous paste and this mix is so
> strong when it sets you can not break it with a hammer  and as lightweight
> as foam.
>
> Now that we have 3D printers we can print moulds and fill the mould with
> this DIY epoxy/carbon paste and in effect print strong-as-steel parts.
>
> I woud cast the ring gear directly inside the aluminum housing so the epoxy
> would bond to the aluminum.   No need to use screws.  The fit would be
> perfect
>
> On Wed, Mar 10, 2021 at 10:58 AM dave engvall 
> wrote:
>
> > PVA seems to be the release agent of choice for epoxy. However, IIUC it
> > has limited shelf life. Silicone oils will work but they tend to migrate
> > to places you
> > don't want them.
> >
> > Dave
> >
> > On 3/10/21 9:31 AM, Chris Albertson wrote:
> > > This is the best and most durable DIY drive I've seen.   One
> > > improvement for the future is to make the internal tooth gears from
> > > something other than 3D printed plastic.  Perhaps you can cast them in
> > > epoxy and fiber composite.   If you used a timing belt as part of the
> > mold
> > > the cast teeth would be as perfect as the belt.
> > >
> > > I can imagine the mold is the square aluminum part with roughened up
> > > internal pocket.  Then stretch a belt over a disk and place the disk in
> > the
> > > pocket leaving a ring then pour in the epoxy.   With luck the epoxy
> bonds
> > > with the aluminum but not with the rubber belt.   Perhaps the belt is
> > > coated in mould release wax.
> > >
> > > On Wed, Mar 10, 2021 at 7:58 AM Sam Sokolik 
> wrote:
> > >
> > >> another update - at 1/2 step - the discrete resolution should be about
> > >> 40,000 divisions per rotation.  .009 deg.
> > >>
> > >> https://www.youtube.com/watch?v=IdfKre6zpEY
> > >>
> > >> On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik 
> wrote:
> > >>
> > >>> https://www.youtube.com/watch?v=ZVVffljc7kE
> > >>>
> > >>> On Tue, Feb 2, 2021 at 9:46 AM Gene Heskett 
> > >> wrote:
> >  On Tuesday 02 February 2021 08:30:56 Sam Sokolik wrote:
> > 
> > > I have looked at cycloidal drives and feel that they have too many
> > > parts :)
> > >
> > > Gene
> > > https://www.youtube.com/watch?v=Gx263nnTrqY
> > >
> > > Ran for over 6 hours like that - about 850rpm input.
> > >
> >  I am highly impressed.
> > 
> >  Now finish the housing, and hang a load on it, like the worm of a
> BS-1
> >  while making another worm to replace the crappy worm in the Chinese
> >  BS-1. That worm is doomed to a higher wear rate, a fact I'm becoming
> >  aware of as I exercise this BS-1 servo for tuning.
> > 
> >  That is why I bought the ender3, but I was using O.P's code which
> was
> >  crappy code IMO. Turns out the ender3 can make stuff a heck of a lot
> >  better that the code I could DL from thingiverse. I now have the
> >  extruder motor on the x carriage, moving a modified stock hot end,
> and
> >  while its slower than some because the heating is only once the
> > filament
> >  is in the nozzle, dozens of times more dependable than the stock
> > setup.
> >  No clogging from cold filament because the hot stuff backs up into
> the
> >  heat sink and freezes.
> > 
> >  I think this loose ring idea has the most promise of making a long
> >  lasting drive, and shorter axially than any design so far. Please
> >  continue.
> > 
> >  Thank you Sam S.
> > 
> > > On Thu, Jan 28, 2021 at 3:13 AM andrew beck <
> > andrewbeck0...@gmail.com
> > > wrote:
> > >> Guys just to chime in here.
> > >>
> > >> Sam went don't you 

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

I've done this a few times.  PVA is best used if the mold is new.  You can
spray in on the mold using an old spray bottle that used to hold kitchen
and bath spray cleaner that is well rinsed out.  But after the mold is used
a few times mould release wax alone is OK.The PVA has some tiny film
thickness and a slight irregular surface and can't be polished.  Wax on the
other hand can be buffed and made to shine.   The part is only as nicely
finished as the mould.   Mould seem to get earlier to release with repeated
use.  PVA dissolves in water, so you can soak the mould and part to release
it.

But it just might be that epoxy does not adhere to rubber and no release
agent is needed.   We never used a release agent on latex rubber moulds.

Carbon fibre parts have this high-tech mystique around them but they can be
made with very crude and low-cost methods using just paper cups,
popsicle sticks and c-clamps.

You can buy one yard of carbon cloth for about $10 and it is a lifetime
supply. Then cut it on bias into 1/8th inch strips and stir the strip until
they become 1/8th inch long unwoven fibers, (or for more money buy "chopped
carbon fiber") mix with epoxy to make a fibrous paste and this mix is so
strong when it sets you can not break it with a hammer  and as lightweight
as foam.

Now that we have 3D printers we can print moulds and fill the mould with
this DIY epoxy/carbon paste and in effect print strong-as-steel parts.

I woud cast the ring gear directly inside the aluminum housing so the epoxy
would bond to the aluminum.   No need to use screws.  The fit would be
perfect

On Wed, Mar 10, 2021 at 10:58 AM dave engvall  wrote:

> PVA seems to be the release agent of choice for epoxy. However, IIUC it
> has limited shelf life. Silicone oils will work but they tend to migrate
> to places you
> don't want them.
>
> Dave
>
> On 3/10/21 9:31 AM, Chris Albertson wrote:
> > This is the best and most durable DIY drive I've seen.   One
> > improvement for the future is to make the internal tooth gears from
> > something other than 3D printed plastic.  Perhaps you can cast them in
> > epoxy and fiber composite.   If you used a timing belt as part of the
> mold
> > the cast teeth would be as perfect as the belt.
> >
> > I can imagine the mold is the square aluminum part with roughened up
> > internal pocket.  Then stretch a belt over a disk and place the disk in
> the
> > pocket leaving a ring then pour in the epoxy.   With luck the epoxy bonds
> > with the aluminum but not with the rubber belt.   Perhaps the belt is
> > coated in mould release wax.
> >
> > On Wed, Mar 10, 2021 at 7:58 AM Sam Sokolik  wrote:
> >
> >> another update - at 1/2 step - the discrete resolution should be about
> >> 40,000 divisions per rotation.  .009 deg.
> >>
> >> https://www.youtube.com/watch?v=IdfKre6zpEY
> >>
> >> On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik  wrote:
> >>
> >>> https://www.youtube.com/watch?v=ZVVffljc7kE
> >>>
> >>> On Tue, Feb 2, 2021 at 9:46 AM Gene Heskett 
> >> wrote:
>  On Tuesday 02 February 2021 08:30:56 Sam Sokolik wrote:
> 
> > I have looked at cycloidal drives and feel that they have too many
> > parts :)
> >
> > Gene
> > https://www.youtube.com/watch?v=Gx263nnTrqY
> >
> > Ran for over 6 hours like that - about 850rpm input.
> >
>  I am highly impressed.
> 
>  Now finish the housing, and hang a load on it, like the worm of a BS-1
>  while making another worm to replace the crappy worm in the Chinese
>  BS-1. That worm is doomed to a higher wear rate, a fact I'm becoming
>  aware of as I exercise this BS-1 servo for tuning.
> 
>  That is why I bought the ender3, but I was using O.P's code which was
>  crappy code IMO. Turns out the ender3 can make stuff a heck of a lot
>  better that the code I could DL from thingiverse. I now have the
>  extruder motor on the x carriage, moving a modified stock hot end, and
>  while its slower than some because the heating is only once the
> filament
>  is in the nozzle, dozens of times more dependable than the stock
> setup.
>  No clogging from cold filament because the hot stuff backs up into the
>  heat sink and freezes.
> 
>  I think this loose ring idea has the most promise of making a long
>  lasting drive, and shorter axially than any design so far. Please
>  continue.
> 
>  Thank you Sam S.
> 
> > On Thu, Jan 28, 2021 at 3:13 AM andrew beck <
> andrewbeck0...@gmail.com
> > wrote:
> >> Guys just to chime in here.
> >>
> >> Sam went don't you design a cycloidal drive instead.  They are easy
> >> to make on a normal 3 axis Cnc mill with a end mill and much more
> >> rigid than a harmonic drive.  As they are not so fragile.  I'm
> >> planning on making some on my VMC soon.I don't understand why
> >> use a harmonic drive.  (I actually have a big harmonic drive here
> >> from a robot. )
> >>
> 

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Karl Schmidt]

What material did you print this in?


On 3/10/21 12:38 PM, Sam Sokolik wrote:

Yes.  The rings can be swapped to change the output direction...  (It can
be made so the stepper turns the same direction as the output shaft..). I
don't know if the friction would be reduced one way or the other...



--

Karl Schmidt  EMail k...@lrak.net
3209 West 9th Street Ph (785) 979-8397
Lawrence, KS 66049



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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

Yes.  The rings can be swapped to change the output direction...  (It can
be made so the stepper turns the same direction as the output shaft..). I
don't know if the friction would be reduced one way or the other...

On Wed, Mar 10, 2021, 12:28 PM Gene Heskett  wrote:

> On Wednesday 10 March 2021 12:54:09 Gene Heskett wrote:
>
> > On Wednesday 10 March 2021 10:55:41 Sam Sokolik wrote:
> > > another update - at 1/2 step - the discrete resolution should be
> > > about 40,000 divisions per rotation.  .009 deg.
> > >
> > > https://www.youtube.com/watch?v=IdfKre6zpEY
> >
> > Pretty darned good Sam, definitely worth pursuing. With 2 bearings
> > covering the width of the ring, the ring should last till the rapture.
> > [...]
> >
> > Cheers, Gene Heskett
>
> But it does bring up a thought. Since the outer rings are the same spline
> pitch diameter, but the teeth are sized to make up the 2 tooth diff in
> the same space, could the upper and lower rings be interchanged to
> reverse the output rings direction? Something in my ancient wet ram says
> one of the two directions would be lower friction. But I'll be switched
> if I can explain why it should be so.
>
> Thanks for your views and or experiences.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
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>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Wednesday 10 March 2021 12:54:09 Gene Heskett wrote:

> On Wednesday 10 March 2021 10:55:41 Sam Sokolik wrote:
> > another update - at 1/2 step - the discrete resolution should be
> > about 40,000 divisions per rotation.  .009 deg.
> >
> > https://www.youtube.com/watch?v=IdfKre6zpEY
>
> Pretty darned good Sam, definitely worth pursuing. With 2 bearings
> covering the width of the ring, the ring should last till the rapture.
> [...]
>
> Cheers, Gene Heskett

But it does bring up a thought. Since the outer rings are the same spline 
pitch diameter, but the teeth are sized to make up the 2 tooth diff in 
the same space, could the upper and lower rings be interchanged to 
reverse the output rings direction? Something in my ancient wet ram says 
one of the two directions would be lower friction. But I'll be switched 
if I can explain why it should be so.

Thanks for your views and or experiences.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Wednesday 10 March 2021 10:55:41 Sam Sokolik wrote:

> another update - at 1/2 step - the discrete resolution should be about
> 40,000 divisions per rotation.  .009 deg.
>
> https://www.youtube.com/watch?v=IdfKre6zpEY
>
Pretty darned good Sam, definitely worth pursuing. With 2 bearings 
covering the width of the ring, the ring should last till the rapture.
[...]

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

This is the best and most durable DIY drive I've seen.   One
improvement for the future is to make the internal tooth gears from
something other than 3D printed plastic.  Perhaps you can cast them in
epoxy and fiber composite.   If you used a timing belt as part of the mold
the cast teeth would be as perfect as the belt.

I can imagine the mold is the square aluminum part with roughened up
internal pocket.  Then stretch a belt over a disk and place the disk in the
pocket leaving a ring then pour in the epoxy.   With luck the epoxy bonds
with the aluminum but not with the rubber belt.   Perhaps the belt is
coated in mould release wax.

On Wed, Mar 10, 2021 at 7:58 AM Sam Sokolik  wrote:

> another update - at 1/2 step - the discrete resolution should be about
> 40,000 divisions per rotation.  .009 deg.
>
> https://www.youtube.com/watch?v=IdfKre6zpEY
>
> On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik  wrote:
>
> > https://www.youtube.com/watch?v=ZVVffljc7kE
> >
> > On Tue, Feb 2, 2021 at 9:46 AM Gene Heskett 
> wrote:
> >
> >> On Tuesday 02 February 2021 08:30:56 Sam Sokolik wrote:
> >>
> >> > I have looked at cycloidal drives and feel that they have too many
> >> > parts :)
> >> >
> >> > Gene
> >> > https://www.youtube.com/watch?v=Gx263nnTrqY
> >> >
> >> > Ran for over 6 hours like that - about 850rpm input.
> >> >
> >> I am highly impressed.
> >>
> >> Now finish the housing, and hang a load on it, like the worm of a BS-1
> >> while making another worm to replace the crappy worm in the Chinese
> >> BS-1. That worm is doomed to a higher wear rate, a fact I'm becoming
> >> aware of as I exercise this BS-1 servo for tuning.
> >>
> >> That is why I bought the ender3, but I was using O.P's code which was
> >> crappy code IMO. Turns out the ender3 can make stuff a heck of a lot
> >> better that the code I could DL from thingiverse. I now have the
> >> extruder motor on the x carriage, moving a modified stock hot end, and
> >> while its slower than some because the heating is only once the filament
> >> is in the nozzle, dozens of times more dependable than the stock setup.
> >> No clogging from cold filament because the hot stuff backs up into the
> >> heat sink and freezes.
> >>
> >> I think this loose ring idea has the most promise of making a long
> >> lasting drive, and shorter axially than any design so far. Please
> >> continue.
> >>
> >> Thank you Sam S.
> >>
> >> > On Thu, Jan 28, 2021 at 3:13 AM andrew beck  >
> >> >
> >> > wrote:
> >> > > Guys just to chime in here.
> >> > >
> >> > > Sam went don't you design a cycloidal drive instead.  They are easy
> >> > > to make on a normal 3 axis Cnc mill with a end mill and much more
> >> > > rigid than a harmonic drive.  As they are not so fragile.  I'm
> >> > > planning on making some on my VMC soon.I don't understand why
> >> > > use a harmonic drive.  (I actually have a big harmonic drive here
> >> > > from a robot. )
> >> > >
> >> > > On Thu, 28 Jan 2021, 18:53 Bari,  wrote:
> >> > > > On 1/27/21 10:55 AM, Sam Sokolik wrote:
> >> > > > > Nice being able to make things while I sleep..
> >> > > > >
> >> > > > > 2 outside side rings - one 202 teeth - one 200 teeth.
> >> > > > > Inside flex ring - 200 teeth.  Feels good - for what it is..
> >> > > > >
> >> > > > >
> http://electronicsam.com/images/greenmachine/IMG_20210127_104237
> >> > > > >.jpg
> >> > > > >
> http://electronicsam.com/images/greenmachine/IMG_20210127_104628
> >> > > > >.jpg
> >> > > > >
> http://electronicsam.com/images/greenmachine/IMG_20210127_104354
> >> > > > >.jpg
> >> > > >
> >> > > > Timing belts will take the flex
> >> > > >
> >> > > > https://www.youtube.com/watch?v=Y8ZELQdgBbU
> >> > > >
> >> > > > https://www.youtube.com/watch?v=2YC-0C8oPUo
> >> > > >
> >> > > >
> >> > > > Cycloid prototype under microscope
> >> > > >
> >> > > > https://www.youtube.com/watch?v=um5GMOBgz6s
> >> > > >
> >> > > >
> >> > > > Hybrid planetary/harmonic drive - check out how they made it flex
> >> > > >
> >> > > > https://www.youtube.com/watch?v=sdRGrTHq4hA
> >> > > >
> >> > > >
> >> > > >
> >> > > > ___
> >> > > > Emc-users mailing list
> >> > > > Emc-users@lists.sourceforge.net
> >> > > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >> > >
> >> > > ___
> >> > > Emc-users mailing list
> >> > > Emc-users@lists.sourceforge.net
> >> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >> >
> >> > ___
> >> > Emc-users mailing list
> >> > Emc-users@lists.sourceforge.net
> >> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >>
> >>
> >> Cheers, Gene Heskett
> >> --
> >> "There are four boxes to be used in defense of liberty:
> >>  soap, ballot, jury, and ammo. Please use in that order."
> >> -Ed Howdershelt (Author)
> >> If we desire respect for the law, we must first make the law
> respectable.
> >>  - Louis D. Brandeis
> >> Genes Web page 

Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

another update - at 1/2 step - the discrete resolution should be about
40,000 divisions per rotation.  .009 deg.

https://www.youtube.com/watch?v=IdfKre6zpEY

On Thu, Feb 4, 2021 at 4:00 PM Sam Sokolik  wrote:

> https://www.youtube.com/watch?v=ZVVffljc7kE
>
> On Tue, Feb 2, 2021 at 9:46 AM Gene Heskett  wrote:
>
>> On Tuesday 02 February 2021 08:30:56 Sam Sokolik wrote:
>>
>> > I have looked at cycloidal drives and feel that they have too many
>> > parts :)
>> >
>> > Gene
>> > https://www.youtube.com/watch?v=Gx263nnTrqY
>> >
>> > Ran for over 6 hours like that - about 850rpm input.
>> >
>> I am highly impressed.
>>
>> Now finish the housing, and hang a load on it, like the worm of a BS-1
>> while making another worm to replace the crappy worm in the Chinese
>> BS-1. That worm is doomed to a higher wear rate, a fact I'm becoming
>> aware of as I exercise this BS-1 servo for tuning.
>>
>> That is why I bought the ender3, but I was using O.P's code which was
>> crappy code IMO. Turns out the ender3 can make stuff a heck of a lot
>> better that the code I could DL from thingiverse. I now have the
>> extruder motor on the x carriage, moving a modified stock hot end, and
>> while its slower than some because the heating is only once the filament
>> is in the nozzle, dozens of times more dependable than the stock setup.
>> No clogging from cold filament because the hot stuff backs up into the
>> heat sink and freezes.
>>
>> I think this loose ring idea has the most promise of making a long
>> lasting drive, and shorter axially than any design so far. Please
>> continue.
>>
>> Thank you Sam S.
>>
>> > On Thu, Jan 28, 2021 at 3:13 AM andrew beck 
>> >
>> > wrote:
>> > > Guys just to chime in here.
>> > >
>> > > Sam went don't you design a cycloidal drive instead.  They are easy
>> > > to make on a normal 3 axis Cnc mill with a end mill and much more
>> > > rigid than a harmonic drive.  As they are not so fragile.  I'm
>> > > planning on making some on my VMC soon.I don't understand why
>> > > use a harmonic drive.  (I actually have a big harmonic drive here
>> > > from a robot. )
>> > >
>> > > On Thu, 28 Jan 2021, 18:53 Bari,  wrote:
>> > > > On 1/27/21 10:55 AM, Sam Sokolik wrote:
>> > > > > Nice being able to make things while I sleep..
>> > > > >
>> > > > > 2 outside side rings - one 202 teeth - one 200 teeth.
>> > > > > Inside flex ring - 200 teeth.  Feels good - for what it is..
>> > > > >
>> > > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104237
>> > > > >.jpg
>> > > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104628
>> > > > >.jpg
>> > > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104354
>> > > > >.jpg
>> > > >
>> > > > Timing belts will take the flex
>> > > >
>> > > > https://www.youtube.com/watch?v=Y8ZELQdgBbU
>> > > >
>> > > > https://www.youtube.com/watch?v=2YC-0C8oPUo
>> > > >
>> > > >
>> > > > Cycloid prototype under microscope
>> > > >
>> > > > https://www.youtube.com/watch?v=um5GMOBgz6s
>> > > >
>> > > >
>> > > > Hybrid planetary/harmonic drive - check out how they made it flex
>> > > >
>> > > > https://www.youtube.com/watch?v=sdRGrTHq4hA
>> > > >
>> > > >
>> > > >
>> > > > ___
>> > > > Emc-users mailing list
>> > > > Emc-users@lists.sourceforge.net
>> > > > https://lists.sourceforge.net/lists/listinfo/emc-users
>> > >
>> > > ___
>> > > Emc-users mailing list
>> > > Emc-users@lists.sourceforge.net
>> > > https://lists.sourceforge.net/lists/listinfo/emc-users
>> >
>> > ___
>> > Emc-users mailing list
>> > Emc-users@lists.sourceforge.net
>> > https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>>
>> Cheers, Gene Heskett
>> --
>> "There are four boxes to be used in defense of liberty:
>>  soap, ballot, jury, and ammo. Please use in that order."
>> -Ed Howdershelt (Author)
>> If we desire respect for the law, we must first make the law respectable.
>>  - Louis D. Brandeis
>> Genes Web page 
>>
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

https://www.youtube.com/watch?v=ZVVffljc7kE

On Tue, Feb 2, 2021 at 9:46 AM Gene Heskett  wrote:

> On Tuesday 02 February 2021 08:30:56 Sam Sokolik wrote:
>
> > I have looked at cycloidal drives and feel that they have too many
> > parts :)
> >
> > Gene
> > https://www.youtube.com/watch?v=Gx263nnTrqY
> >
> > Ran for over 6 hours like that - about 850rpm input.
> >
> I am highly impressed.
>
> Now finish the housing, and hang a load on it, like the worm of a BS-1
> while making another worm to replace the crappy worm in the Chinese
> BS-1. That worm is doomed to a higher wear rate, a fact I'm becoming
> aware of as I exercise this BS-1 servo for tuning.
>
> That is why I bought the ender3, but I was using O.P's code which was
> crappy code IMO. Turns out the ender3 can make stuff a heck of a lot
> better that the code I could DL from thingiverse. I now have the
> extruder motor on the x carriage, moving a modified stock hot end, and
> while its slower than some because the heating is only once the filament
> is in the nozzle, dozens of times more dependable than the stock setup.
> No clogging from cold filament because the hot stuff backs up into the
> heat sink and freezes.
>
> I think this loose ring idea has the most promise of making a long
> lasting drive, and shorter axially than any design so far. Please
> continue.
>
> Thank you Sam S.
>
> > On Thu, Jan 28, 2021 at 3:13 AM andrew beck 
> >
> > wrote:
> > > Guys just to chime in here.
> > >
> > > Sam went don't you design a cycloidal drive instead.  They are easy
> > > to make on a normal 3 axis Cnc mill with a end mill and much more
> > > rigid than a harmonic drive.  As they are not so fragile.  I'm
> > > planning on making some on my VMC soon.I don't understand why
> > > use a harmonic drive.  (I actually have a big harmonic drive here
> > > from a robot. )
> > >
> > > On Thu, 28 Jan 2021, 18:53 Bari,  wrote:
> > > > On 1/27/21 10:55 AM, Sam Sokolik wrote:
> > > > > Nice being able to make things while I sleep..
> > > > >
> > > > > 2 outside side rings - one 202 teeth - one 200 teeth.
> > > > > Inside flex ring - 200 teeth.  Feels good - for what it is..
> > > > >
> > > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104237
> > > > >.jpg
> > > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104628
> > > > >.jpg
> > > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104354
> > > > >.jpg
> > > >
> > > > Timing belts will take the flex
> > > >
> > > > https://www.youtube.com/watch?v=Y8ZELQdgBbU
> > > >
> > > > https://www.youtube.com/watch?v=2YC-0C8oPUo
> > > >
> > > >
> > > > Cycloid prototype under microscope
> > > >
> > > > https://www.youtube.com/watch?v=um5GMOBgz6s
> > > >
> > > >
> > > > Hybrid planetary/harmonic drive - check out how they made it flex
> > > >
> > > > https://www.youtube.com/watch?v=sdRGrTHq4hA
> > > >
> > > >
> > > >
> > > > ___
> > > > Emc-users mailing list
> > > > Emc-users@lists.sourceforge.net
> > > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Tuesday 02 February 2021 08:30:56 Sam Sokolik wrote:

> I have looked at cycloidal drives and feel that they have too many
> parts :)
>
> Gene
> https://www.youtube.com/watch?v=Gx263nnTrqY
>
> Ran for over 6 hours like that - about 850rpm input.
>
I am highly impressed.

Now finish the housing, and hang a load on it, like the worm of a BS-1 
while making another worm to replace the crappy worm in the Chinese 
BS-1. That worm is doomed to a higher wear rate, a fact I'm becoming 
aware of as I exercise this BS-1 servo for tuning. 

That is why I bought the ender3, but I was using O.P's code which was 
crappy code IMO. Turns out the ender3 can make stuff a heck of a lot 
better that the code I could DL from thingiverse. I now have the 
extruder motor on the x carriage, moving a modified stock hot end, and 
while its slower than some because the heating is only once the filament 
is in the nozzle, dozens of times more dependable than the stock setup. 
No clogging from cold filament because the hot stuff backs up into the 
heat sink and freezes.

I think this loose ring idea has the most promise of making a long 
lasting drive, and shorter axially than any design so far. Please 
continue.

Thank you Sam S.

> On Thu, Jan 28, 2021 at 3:13 AM andrew beck 
>
> wrote:
> > Guys just to chime in here.
> >
> > Sam went don't you design a cycloidal drive instead.  They are easy
> > to make on a normal 3 axis Cnc mill with a end mill and much more
> > rigid than a harmonic drive.  As they are not so fragile.  I'm
> > planning on making some on my VMC soon.I don't understand why
> > use a harmonic drive.  (I actually have a big harmonic drive here
> > from a robot. )
> >
> > On Thu, 28 Jan 2021, 18:53 Bari,  wrote:
> > > On 1/27/21 10:55 AM, Sam Sokolik wrote:
> > > > Nice being able to make things while I sleep..
> > > >
> > > > 2 outside side rings - one 202 teeth - one 200 teeth.
> > > > Inside flex ring - 200 teeth.  Feels good - for what it is..
> > > >
> > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104237
> > > >.jpg
> > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104628
> > > >.jpg
> > > > http://electronicsam.com/images/greenmachine/IMG_20210127_104354
> > > >.jpg
> > >
> > > Timing belts will take the flex
> > >
> > > https://www.youtube.com/watch?v=Y8ZELQdgBbU
> > >
> > > https://www.youtube.com/watch?v=2YC-0C8oPUo
> > >
> > >
> > > Cycloid prototype under microscope
> > >
> > > https://www.youtube.com/watch?v=um5GMOBgz6s
> > >
> > >
> > > Hybrid planetary/harmonic drive - check out how they made it flex
> > >
> > > https://www.youtube.com/watch?v=sdRGrTHq4hA
> > >
> > >
> > >
> > > ___
> > > Emc-users mailing list
> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
>
> ___
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

I have looked at cycloidal drives and feel that they have too many parts :)

Gene
https://www.youtube.com/watch?v=Gx263nnTrqY

Ran for over 6 hours like that - about 850rpm input.


On Thu, Jan 28, 2021 at 3:13 AM andrew beck 
wrote:

> Guys just to chime in here.
>
> Sam went don't you design a cycloidal drive instead.  They are easy to make
> on a normal 3 axis Cnc mill with a end mill and much more rigid than a
> harmonic drive.  As they are not so fragile.  I'm planning on making some
> on my VMC soon.I don't understand why use a harmonic drive.  (I
> actually have a big harmonic drive here from a robot. )
>
> On Thu, 28 Jan 2021, 18:53 Bari,  wrote:
>
> > On 1/27/21 10:55 AM, Sam Sokolik wrote:
> >
> > > Nice being able to make things while I sleep..
> > >
> > > 2 outside side rings - one 202 teeth - one 200 teeth.
> > > Inside flex ring - 200 teeth.  Feels good - for what it is..
> > >
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg
> > >
> > Timing belts will take the flex
> >
> > https://www.youtube.com/watch?v=Y8ZELQdgBbU
> >
> > https://www.youtube.com/watch?v=2YC-0C8oPUo
> >
> >
> > Cycloid prototype under microscope
> >
> > https://www.youtube.com/watch?v=um5GMOBgz6s
> >
> >
> > Hybrid planetary/harmonic drive - check out how they made it flex
> >
> > https://www.youtube.com/watch?v=sdRGrTHq4hA
> >
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
> ___
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[andrew beck]

Guys just to chime in here.

Sam went don't you design a cycloidal drive instead.  They are easy to make
on a normal 3 axis Cnc mill with a end mill and much more rigid than a
harmonic drive.  As they are not so fragile.  I'm planning on making some
on my VMC soon.I don't understand why use a harmonic drive.  (I
actually have a big harmonic drive here from a robot. )

On Thu, 28 Jan 2021, 18:53 Bari,  wrote:

> On 1/27/21 10:55 AM, Sam Sokolik wrote:
>
> > Nice being able to make things while I sleep..
> >
> > 2 outside side rings - one 202 teeth - one 200 teeth.
> > Inside flex ring - 200 teeth.  Feels good - for what it is..
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg
> >
> Timing belts will take the flex
>
> https://www.youtube.com/watch?v=Y8ZELQdgBbU
>
> https://www.youtube.com/watch?v=2YC-0C8oPUo
>
>
> Cycloid prototype under microscope
>
> https://www.youtube.com/watch?v=um5GMOBgz6s
>
>
> Hybrid planetary/harmonic drive - check out how they made it flex
>
> https://www.youtube.com/watch?v=sdRGrTHq4hA
>
>
>
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Bari]

On 1/27/21 10:55 AM, Sam Sokolik wrote:


Nice being able to make things while I sleep..

2 outside side rings - one 202 teeth - one 200 teeth.
Inside flex ring - 200 teeth.  Feels good - for what it is..

http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg


Timing belts will take the flex

https://www.youtube.com/watch?v=Y8ZELQdgBbU

https://www.youtube.com/watch?v=2YC-0C8oPUo


Cycloid prototype under microscope

https://www.youtube.com/watch?v=um5GMOBgz6s


Hybrid planetary/harmonic drive - check out how they made it flex

https://www.youtube.com/watch?v=sdRGrTHq4hA



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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gregg Eshelman via Emc-users]

A dual bearing block on both sides. Mount the 200 tooth ring to one block and 
the 200+ tooth ring to the shaft on the other for the output. Mount the bar 
with rollers to the other shaft and there's your drive. Put a little flange in 
both rings to keep the flex ring centered. Lube it all very well with silicone 
grease.


 

On Wednesday, January 27, 2021, 9:13:20 PM MST, Sam Sokolik 
 wrote:  
 
 https://youtu.be/nhHDrK6sCRs

On Wed, Jan 27, 2021 at 3:56 PM Gene Heskett  wrote:

> On Wednesday 27 January 2021 16:04:45 Chris Albertson wrote:
>
> > This is a machine-tool related list.  Many of us have 3D printers
> > too. So if you have both additive and subtractive tools available and
> > want to make a harmonic drive may be the best option is to make a
> > hybrid design with some parts of the drive made with different
> > techniques.
> >
> > Metal really is the best material for anything that needs to flex
> > because metal can be made so thin and is still strong when thin.  3D
> > printed plastic must be about the worst material for this.
> >
> > So I ask, Would it be possible to design an easy to make flex gear?
> > I think so.  Most of the flex cup is made on a lathe then you mill
> > the teeth on the outside.  I think it could be machined from a short
> > section of large-diameter steel tube.  Then a bottom plate is press
> > fit.
> >
> > Maybe I could cut the teeth first, like making a gear, then place the
> > part in plastic holder and chuck the holder in a lathe and bore the
> > center out until the ring is very thin.  The trick is to support the
> > ring with a 3D printed rigid backing fixture while boring it.
> >
> > The rest of the harmonic drive could be plastic.
> >
> > The big question for the group here is if the flex ring is something a
> > normal person could make one at a time.  What kind of metal is best?
> > Is this kind of metal available in tiny quanity
> >
> > On Wed, Jan 27, 2021 at 12:36 PM Gregg Eshelman via Emc-users <
> >
> > emc-users@lists.sourceforge.net> wrote:
> > > Instead of a one piece flex cup, how about making a flex ring that
> > > connects to a rigid base with teeth or pins - something that
> > > interlocks but allows radial movement of the flex ring with respect
> > > to the base? No constant bending back and forth to break the print
> > > layers apart.
>
> I like this idea too. Cut or 3d print, the equ of a small pitch box joint
> on the bottom of the flex gear, matched to engage the "fingers" on the
> output disk, it could slid in and out radially on these "box": pins, and
> do it without the flex that normally breaks the cup off the disk at that
> joint. That would replace the spot that is the major breaking point,
> with a hinge like joint, which might prolong its life by many times what
> it is now.
>
> The splined part would then need to be restrained axially to keep it from
> wearing the ends of the cylinder it becomes, from rubbing on the
> housing. Perhaps a very mild dovetail? But that would lead to backlash
> and problems assembling it.
>
> Enough extra length on the cups pins to project a thou or so past the
> disk and drive a flat head 0-80 screw in the the end of the pin, pin
> sized so the angled underside of the head would prevent it from pulling
> apart. Wouldn't take a screw per pin, one in every 4th or 5th pins
> should do it. 3d print a bit of the 0-80's underside head angle on the
> disks fingers and screw head could actually sit below the disk face.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gregg Eshelman via Emc-users]

How about a semi-rigid urethane adhesive bonding the flex ring to a rigid metal 
hub? Have some interlocking features on the inside of the ring and edge of the 
hub to keep it from shearing apart. Smooth-On makes a primer called UreBond II 
that makes their urethane resins and rubbers stick to almost anything.


On Wednesday, January 27, 2021, 2:14:26 PM MST, Gene Heskett 
 wrote:  
 
 On Wednesday 27 January 2021 15:35:00 Gregg Eshelman via Emc-users wrote:

> Instead of a one piece flex cup, how about making a flex ring that
> connects to a rigid base with teeth or pins - something that
> interlocks but allows radial movement of the flex ring with respect to
> the base? No constant bending back and forth to break the print layers
> apart.

I can visualize that but with only one bearing on the driver armature, so 
the formerly flex ring is trapped between the bearing and the outer 2 
parts. This would have the added advantage of needing only a 1 tooth 
difference, but would probably need a counterweight opposite the bearing 
as we've seen in cycloid designs, probably weighing as much as the 
bearing and floating ring combined for decent balance.

Or, still thinking outside the box, even the triplet of small bearings on 
one end of the driving armature. Or better yet, a circular disk with a 
lot of empty space in it to keep the ring from flexing so much as it 
fly's around, with a smaller cheaper bearing centered in that disk, but 
being swung on an offcenter pin on the driving axle. With Sams fine 
teeth, but only a 1 tooth difference, a possible 400/1 ratio?

The moving output ring might need to be restrained from resonane effects 
by a BIG and costly bearing in the final version but bolted to a stiff 
disk with a smaller double bearing'd output shaft might do for testing 
to see if its practical.  
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

https://youtu.be/nhHDrK6sCRs

On Wed, Jan 27, 2021 at 3:56 PM Gene Heskett  wrote:

> On Wednesday 27 January 2021 16:04:45 Chris Albertson wrote:
>
> > This is a machine-tool related list.   Many of us have 3D printers
> > too. So if you have both additive and subtractive tools available and
> > want to make a harmonic drive may be the best option is to make a
> > hybrid design with some parts of the drive made with different
> > techniques.
> >
> > Metal really is the best material for anything that needs to flex
> > because metal can be made so thin and is still strong when thin.   3D
> > printed plastic must be about the worst material for this.
> >
> > So I ask, Would it be possible to design an easy to make flex gear?
> > I think so.   Most of the flex cup is made on a lathe then you mill
> > the teeth on the outside.  I think it could be machined from a short
> > section of large-diameter steel tube.  Then a bottom plate is press
> > fit.
> >
> > Maybe I could cut the teeth first, like making a gear, then place the
> > part in plastic holder and chuck the holder in a lathe and bore the
> > center out until the ring is very thin.   The trick is to support the
> > ring with a 3D printed rigid backing fixture while boring it.
> >
> > The rest of the harmonic drive could be plastic.
> >
> > The big question for the group here is if the flex ring is something a
> > normal person could make one at a time.  What kind of metal is best?
> > Is this kind of metal available in tiny quanity
> >
> > On Wed, Jan 27, 2021 at 12:36 PM Gregg Eshelman via Emc-users <
> >
> > emc-users@lists.sourceforge.net> wrote:
> > > Instead of a one piece flex cup, how about making a flex ring that
> > > connects to a rigid base with teeth or pins - something that
> > > interlocks but allows radial movement of the flex ring with respect
> > > to the base? No constant bending back and forth to break the print
> > > layers apart.
>
> I like this idea too. Cut or 3d print, the equ of a small pitch box joint
> on the bottom of the flex gear, matched to engage the "fingers" on the
> output disk, it could slid in and out radially on these "box": pins, and
> do it without the flex that normally breaks the cup off the disk at that
> joint. That would replace the spot that is the major breaking point,
> with a hinge like joint, which might prolong its life by many times what
> it is now.
>
> The splined part would then need to be restrained axially to keep it from
> wearing the ends of the cylinder it becomes, from rubbing on the
> housing. Perhaps a very mild dovetail? But that would lead to backlash
> and problems assembling it.
>
> Enough extra length on the cups pins to project a thou or so past the
> disk and drive a flat head 0-80 screw in the the end of the pin, pin
> sized so the angled underside of the head would prevent it from pulling
> apart. Wouldn't take a screw per pin, one in every 4th or 5th pins
> should do it. 3d print a bit of the 0-80's underside head angle on the
> disks fingers and screw head could actually sit below the disk face.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Wednesday 27 January 2021 16:04:45 Chris Albertson wrote:

> This is a machine-tool related list.   Many of us have 3D printers
> too. So if you have both additive and subtractive tools available and
> want to make a harmonic drive may be the best option is to make a
> hybrid design with some parts of the drive made with different
> techniques.
>
> Metal really is the best material for anything that needs to flex
> because metal can be made so thin and is still strong when thin.   3D
> printed plastic must be about the worst material for this.
>
> So I ask, Would it be possible to design an easy to make flex gear?  
> I think so.   Most of the flex cup is made on a lathe then you mill
> the teeth on the outside.  I think it could be machined from a short
> section of large-diameter steel tube.  Then a bottom plate is press
> fit.
>
> Maybe I could cut the teeth first, like making a gear, then place the
> part in plastic holder and chuck the holder in a lathe and bore the
> center out until the ring is very thin.   The trick is to support the
> ring with a 3D printed rigid backing fixture while boring it.
>
> The rest of the harmonic drive could be plastic.
>
> The big question for the group here is if the flex ring is something a
> normal person could make one at a time.  What kind of metal is best? 
> Is this kind of metal available in tiny quanity
>
> On Wed, Jan 27, 2021 at 12:36 PM Gregg Eshelman via Emc-users <
>
> emc-users@lists.sourceforge.net> wrote:
> > Instead of a one piece flex cup, how about making a flex ring that
> > connects to a rigid base with teeth or pins - something that
> > interlocks but allows radial movement of the flex ring with respect
> > to the base? No constant bending back and forth to break the print
> > layers apart.

I like this idea too. Cut or 3d print, the equ of a small pitch box joint 
on the bottom of the flex gear, matched to engage the "fingers" on the 
output disk, it could slid in and out radially on these "box": pins, and 
do it without the flex that normally breaks the cup off the disk at that 
joint. That would replace the spot that is the major breaking point, 
with a hinge like joint, which might prolong its life by many times what 
it is now.

The splined part would then need to be restrained axially to keep it from 
wearing the ends of the cylinder it becomes, from rubbing on the 
housing. Perhaps a very mild dovetail? But that would lead to backlash 
and problems assembling it.

Enough extra length on the cups pins to project a thou or so past the 
disk and drive a flat head 0-80 screw in the the end of the pin, pin 
sized so the angled underside of the head would prevent it from pulling 
apart. Wouldn't take a screw per pin, one in every 4th or 5th pins 
should do it. 3d print a bit of the 0-80's underside head angle on the 
disks fingers and screw head could actually sit below the disk face.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[andy pugh]

On Wed, 27 Jan 2021 at 21:07, Chris Albertson  wrote:

> So I ask, Would it be possible to design an easy to make flex gear?   I
> think so.

I am not so sure. In fact I am so not-sure that I am building an EDM
grinder to make hardened (or carbide) tooling with the right profile.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gene Heskett]

On Wednesday 27 January 2021 15:35:00 Gregg Eshelman via Emc-users wrote:

> Instead of a one piece flex cup, how about making a flex ring that
> connects to a rigid base with teeth or pins - something that
> interlocks but allows radial movement of the flex ring with respect to
> the base? No constant bending back and forth to break the print layers
> apart.

I can visualize that but with only one bearing on the driver armature, so 
the formerly flex ring is trapped between the bearing and the outer 2 
parts. This would have the added advantage of needing only a 1 tooth 
difference, but would probably need a counterweight opposite the bearing 
as we've seen in cycloid designs, probably weighing as much as the 
bearing and floating ring combined for decent balance.

Or, still thinking outside the box, even the triplet of small bearings on 
one end of the driving armature. Or better yet, a circular disk with a 
lot of empty space in it to keep the ring from flexing so much as it 
fly's around, with a smaller cheaper bearing centered in that disk, but 
being swung on an offcenter pin on the driving axle. With Sams fine 
teeth, but only a 1 tooth difference, a possible 400/1 ratio?

The moving output ring might need to be restrained from resonane effects 
by a BIG and costly bearing in the final version but bolted to a stiff 
disk with a smaller double bearing'd output shaft might do for testing 
to see if its practical.

> On Wednesday, January 27, 2021, 12:06:27 PM MST, Sam Sokolik
>  wrote:
>
>  well - that is the plan... but I need to create a decent housing to
> mount it all...  :)  SMOM  (simple matter of machining)
>
> On Wed, Jan 27, 2021 at 12:59 PM Chris Albertson
> 
>
> wrote:
> > Now, if you will, place it on a motor and run it for 24 hours and
> > let us know what happens.
> >
> > On Wed, Jan 27, 2021 at 8:59 AM Sam Sokolik  
wrote:
> > > Nice being able to make things while I sleep..
> > >
> > > 2 outside side rings - one 202 teeth - one 200 teeth.
> > > Inside flex ring - 200 teeth.  Feels good - for what it is..
> > >
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104237.j
> > >pg
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104628.j
> > >pg
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104354.j
> > >pg

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

This is a machine-tool related list.   Many of us have 3D printers too.
 So if you have both additive and subtractive tools available and want to
make a harmonic drive may be the best option is to make a hybrid design
with some parts of the drive made with different techniques.

Metal really is the best material for anything that needs to flex because
metal can be made so thin and is still strong when thin.   3D printed
plastic must be about the worst material for this.

So I ask, Would it be possible to design an easy to make flex gear?   I
think so.   Most of the flex cup is made on a lathe then you mill the teeth
on the outside.  I think it could be machined from a short section of
large-diameter steel tube.  Then a bottom plate is press fit.

Maybe I could cut the teeth first, like making a gear, then place the part
in plastic holder and chuck the holder in a lathe and bore the center out
until the ring is very thin.   The trick is to support the ring with a 3D
printed rigid backing fixture while boring it.

The rest of the harmonic drive could be plastic.

The big question for the group here is if the flex ring is something a
normal person could make one at a time.  What kind of metal is best?  Is
this kind of metal available in tiny quanity

On Wed, Jan 27, 2021 at 12:36 PM Gregg Eshelman via Emc-users <
emc-users@lists.sourceforge.net> wrote:

> Instead of a one piece flex cup, how about making a flex ring that
> connects to a rigid base with teeth or pins - something that interlocks but
> allows radial movement of the flex ring with respect to the base? No
> constant bending back and forth to break the print layers apart.
>
-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Gregg Eshelman via Emc-users]

Instead of a one piece flex cup, how about making a flex ring that connects to 
a rigid base with teeth or pins - something that interlocks but allows radial 
movement of the flex ring with respect to the base? No constant bending back 
and forth to break the print layers apart.


On Wednesday, January 27, 2021, 12:06:27 PM MST, Sam Sokolik 
 wrote:  
 
 well - that is the plan... but I need to create a decent housing to mount
it all...  :)  SMOM  (simple matter of machining)

On Wed, Jan 27, 2021 at 12:59 PM Chris Albertson 
wrote:

> Now, if you will, place it on a motor and run it for 24 hours and let us
> know what happens.
>
> On Wed, Jan 27, 2021 at 8:59 AM Sam Sokolik  wrote:
>
> > Nice being able to make things while I sleep..
> >
> > 2 outside side rings - one 202 teeth - one 200 teeth.
> > Inside flex ring - 200 teeth.  Feels good - for what it is..
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg  
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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

For tests I tend to do things like clamp it to a drill press table and
power it with the chuck.,  Or even use a hand-held drill motor to very if
gears mesh.  What I've found is plastic gears need to be about 3X larger
than metal ones.

On Wed, Jan 27, 2021 at 11:06 AM Sam Sokolik  wrote:

> well - that is the plan... but I need to create a decent housing to mount
> it all...  :)  SMOM  (simple matter of machining)
>
> On Wed, Jan 27, 2021 at 12:59 PM Chris Albertson <
> albertson.ch...@gmail.com>
> wrote:
>
> > Now, if you will, place it on a motor and run it for 24 hours and let us
> > know what happens.
> >
> > On Wed, Jan 27, 2021 at 8:59 AM Sam Sokolik  wrote:
> >
> > > Nice being able to make things while I sleep..
> > >
> > > 2 outside side rings - one 202 teeth - one 200 teeth.
> > > Inside flex ring - 200 teeth.  Feels good - for what it is..
> > >
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
> > > http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg
> > >
> > >
> > >
> > >
> > > On Tue, Jan 26, 2021 at 10:37 PM Sam Sokolik 
> wrote:
> > >
> > > > I will give it a try - printing a 200 tooth and a taller 200 tooth
> flex
> > > > gear.
> > > >
> > > > http://electronicsam.com/images/greenmachine/IMG_20210126_22.jpg
> > > >
> > > > On Tue, Jan 26, 2021 at 8:07 PM Chris Albertson <
> > > albertson.ch...@gmail.com>
> > > > wrote:
> > > >
> > > >> I could read it well enough to see that they only quote prices.
> > The
> > > >> old saying is that if you have to ask the price you can't afford it.
> > > >>
> > > >> I can see where plastic gearboxes might be a good solution in
> perhaps
> > > food
> > > >> service or other places where you can't have contamination from
> > > >> lubricants.  Or maybe if you need to have it work while in contact
> > with
> > > >> saltwater.
> > > >>
> > > >> On Tue, Jan 26, 2021 at 3:27 PM andy pugh 
> wrote:
> > > >>
> > > >> > On Tue, 26 Jan 2021 at 22:38, Chris Albertson <
> > > >> albertson.ch...@gmail.com>
> > > >> > wrote:
> > > >> > >
> > > >> > > Igus makes 1st rate stuff.
> > > >> > ...
> > > >> > > My German language skill is minimal
> > > >> > > but it appears prices are quoted, not posted online.
> > > >> >
> > > >> > English: https://www.igus.co.uk/product/20413
> > > >> >
> > > >> > (Also available in dozens of other languages by pressing the
> > language
> > > >> > button top-right)
> > > >> >
> > > >> > --
> > > >> > atp
> > > >> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > > >> > designed for the especial use of mechanical geniuses, daredevils
> and
> > > >> > lunatics."
> > > >> > — George Fitch, Atlanta Constitution Newspaper, 1912
> > > >> >
> > > >> >
> > > >> > ___
> > > >> > Emc-users mailing list
> > > >> > Emc-users@lists.sourceforge.net
> > > >> > https://lists.sourceforge.net/lists/listinfo/emc-users
> > > >> >
> > > >>
> > > >>
> > > >> --
> > > >>
> > > >> Chris Albertson
> > > >> Redondo Beach, California
> > > >>
> > > >> ___
> > > >> Emc-users mailing list
> > > >> Emc-users@lists.sourceforge.net
> > > >> https://lists.sourceforge.net/lists/listinfo/emc-users
> > > >>
> > > >
> > >
> > > ___
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> > > Emc-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/emc-users
> > >
> >
> >
> > --
> >
> > Chris Albertson
> > Redondo Beach, California
> >
> > ___
> > Emc-users mailing list
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> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
> ___
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>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

well - that is the plan... but I need to create a decent housing to mount
it all...  :)  SMOM  (simple matter of machining)

On Wed, Jan 27, 2021 at 12:59 PM Chris Albertson 
wrote:

> Now, if you will, place it on a motor and run it for 24 hours and let us
> know what happens.
>
> On Wed, Jan 27, 2021 at 8:59 AM Sam Sokolik  wrote:
>
> > Nice being able to make things while I sleep..
> >
> > 2 outside side rings - one 202 teeth - one 200 teeth.
> > Inside flex ring - 200 teeth.  Feels good - for what it is..
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
> > http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg
> >
> >
> >
> >
> > On Tue, Jan 26, 2021 at 10:37 PM Sam Sokolik  wrote:
> >
> > > I will give it a try - printing a 200 tooth and a taller 200 tooth flex
> > > gear.
> > >
> > > http://electronicsam.com/images/greenmachine/IMG_20210126_22.jpg
> > >
> > > On Tue, Jan 26, 2021 at 8:07 PM Chris Albertson <
> > albertson.ch...@gmail.com>
> > > wrote:
> > >
> > >> I could read it well enough to see that they only quote prices.
> The
> > >> old saying is that if you have to ask the price you can't afford it.
> > >>
> > >> I can see where plastic gearboxes might be a good solution in perhaps
> > food
> > >> service or other places where you can't have contamination from
> > >> lubricants.  Or maybe if you need to have it work while in contact
> with
> > >> saltwater.
> > >>
> > >> On Tue, Jan 26, 2021 at 3:27 PM andy pugh  wrote:
> > >>
> > >> > On Tue, 26 Jan 2021 at 22:38, Chris Albertson <
> > >> albertson.ch...@gmail.com>
> > >> > wrote:
> > >> > >
> > >> > > Igus makes 1st rate stuff.
> > >> > ...
> > >> > > My German language skill is minimal
> > >> > > but it appears prices are quoted, not posted online.
> > >> >
> > >> > English: https://www.igus.co.uk/product/20413
> > >> >
> > >> > (Also available in dozens of other languages by pressing the
> language
> > >> > button top-right)
> > >> >
> > >> > --
> > >> > atp
> > >> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > >> > designed for the especial use of mechanical geniuses, daredevils and
> > >> > lunatics."
> > >> > — George Fitch, Atlanta Constitution Newspaper, 1912
> > >> >
> > >> >
> > >> > ___
> > >> > Emc-users mailing list
> > >> > Emc-users@lists.sourceforge.net
> > >> > https://lists.sourceforge.net/lists/listinfo/emc-users
> > >> >
> > >>
> > >>
> > >> --
> > >>
> > >> Chris Albertson
> > >> Redondo Beach, California
> > >>
> > >> ___
> > >> Emc-users mailing list
> > >> Emc-users@lists.sourceforge.net
> > >> https://lists.sourceforge.net/lists/listinfo/emc-users
> > >>
> > >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
> ___
> Emc-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Chris Albertson]

Now, if you will, place it on a motor and run it for 24 hours and let us
know what happens.

On Wed, Jan 27, 2021 at 8:59 AM Sam Sokolik  wrote:

> Nice being able to make things while I sleep..
>
> 2 outside side rings - one 202 teeth - one 200 teeth.
> Inside flex ring - 200 teeth.  Feels good - for what it is..
>
> http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
> http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
> http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg
>
>
>
>
> On Tue, Jan 26, 2021 at 10:37 PM Sam Sokolik  wrote:
>
> > I will give it a try - printing a 200 tooth and a taller 200 tooth flex
> > gear.
> >
> > http://electronicsam.com/images/greenmachine/IMG_20210126_22.jpg
> >
> > On Tue, Jan 26, 2021 at 8:07 PM Chris Albertson <
> albertson.ch...@gmail.com>
> > wrote:
> >
> >> I could read it well enough to see that they only quote prices.  The
> >> old saying is that if you have to ask the price you can't afford it.
> >>
> >> I can see where plastic gearboxes might be a good solution in perhaps
> food
> >> service or other places where you can't have contamination from
> >> lubricants.  Or maybe if you need to have it work while in contact with
> >> saltwater.
> >>
> >> On Tue, Jan 26, 2021 at 3:27 PM andy pugh  wrote:
> >>
> >> > On Tue, 26 Jan 2021 at 22:38, Chris Albertson <
> >> albertson.ch...@gmail.com>
> >> > wrote:
> >> > >
> >> > > Igus makes 1st rate stuff.
> >> > ...
> >> > > My German language skill is minimal
> >> > > but it appears prices are quoted, not posted online.
> >> >
> >> > English: https://www.igus.co.uk/product/20413
> >> >
> >> > (Also available in dozens of other languages by pressing the language
> >> > button top-right)
> >> >
> >> > --
> >> > atp
> >> > "A motorcycle is a bicycle with a pandemonium attachment and is
> >> > designed for the especial use of mechanical geniuses, daredevils and
> >> > lunatics."
> >> > — George Fitch, Atlanta Constitution Newspaper, 1912
> >> >
> >> >
> >> > ___
> >> > Emc-users mailing list
> >> > Emc-users@lists.sourceforge.net
> >> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >> >
> >>
> >>
> >> --
> >>
> >> Chris Albertson
> >> Redondo Beach, California
> >>
> >> ___
> >> Emc-users mailing list
> >> Emc-users@lists.sourceforge.net
> >> https://lists.sourceforge.net/lists/listinfo/emc-users
> >>
> >
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

Nice being able to make things while I sleep..

2 outside side rings - one 202 teeth - one 200 teeth.
Inside flex ring - 200 teeth.  Feels good - for what it is..

http://electronicsam.com/images/greenmachine/IMG_20210127_104237.jpg
http://electronicsam.com/images/greenmachine/IMG_20210127_104628.jpg
http://electronicsam.com/images/greenmachine/IMG_20210127_104354.jpg




On Tue, Jan 26, 2021 at 10:37 PM Sam Sokolik  wrote:

> I will give it a try - printing a 200 tooth and a taller 200 tooth flex
> gear.
>
> http://electronicsam.com/images/greenmachine/IMG_20210126_22.jpg
>
> On Tue, Jan 26, 2021 at 8:07 PM Chris Albertson 
> wrote:
>
>> I could read it well enough to see that they only quote prices.  The
>> old saying is that if you have to ask the price you can't afford it.
>>
>> I can see where plastic gearboxes might be a good solution in perhaps food
>> service or other places where you can't have contamination from
>> lubricants.  Or maybe if you need to have it work while in contact with
>> saltwater.
>>
>> On Tue, Jan 26, 2021 at 3:27 PM andy pugh  wrote:
>>
>> > On Tue, 26 Jan 2021 at 22:38, Chris Albertson <
>> albertson.ch...@gmail.com>
>> > wrote:
>> > >
>> > > Igus makes 1st rate stuff.
>> > ...
>> > > My German language skill is minimal
>> > > but it appears prices are quoted, not posted online.
>> >
>> > English: https://www.igus.co.uk/product/20413
>> >
>> > (Also available in dozens of other languages by pressing the language
>> > button top-right)
>> >
>> > --
>> > atp
>> > "A motorcycle is a bicycle with a pandemonium attachment and is
>> > designed for the especial use of mechanical geniuses, daredevils and
>> > lunatics."
>> > — George Fitch, Atlanta Constitution Newspaper, 1912
>> >
>> >
>> > ___
>> > Emc-users mailing list
>> > Emc-users@lists.sourceforge.net
>> > https://lists.sourceforge.net/lists/listinfo/emc-users
>> >
>>
>>
>> --
>>
>> Chris Albertson
>> Redondo Beach, California
>>
>> ___
>> Emc-users mailing list
>> Emc-users@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>

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Re: [Emc-users] Maybe a minimally printed harmonic drive?

[Sam Sokolik]

I will give it a try - printing a 200 tooth and a taller 200 tooth flex
gear.

http://electronicsam.com/images/greenmachine/IMG_20210126_22.jpg

On Tue, Jan 26, 2021 at 8:07 PM Chris Albertson 
wrote:

> I could read it well enough to see that they only quote prices.  The
> old saying is that if you have to ask the price you can't afford it.
>
> I can see where plastic gearboxes might be a good solution in perhaps food
> service or other places where you can't have contamination from
> lubricants.  Or maybe if you need to have it work while in contact with
> saltwater.
>
> On Tue, Jan 26, 2021 at 3:27 PM andy pugh  wrote:
>
> > On Tue, 26 Jan 2021 at 22:38, Chris Albertson  >
> > wrote:
> > >
> > > Igus makes 1st rate stuff.
> > ...
> > > My German language skill is minimal
> > > but it appears prices are quoted, not posted online.
> >
> > English: https://www.igus.co.uk/product/20413
> >
> > (Also available in dozens of other languages by pressing the language
> > button top-right)
> >
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> > — George Fitch, Atlanta Constitution Newspaper, 1912
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users
> >
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>

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