Re: [Emc-users] Printer working, need involute gear designer

[Gene Heskett]

On Thursday 18 June 2020 17:31:52 marcus.bow...@visible.eclipse.co.uk 
wrote:

> Gene,
>
> Have you looked at www.gearotic.com
> or did someone mention that already?
>
> Marcus

No. I downloaded it, but its a winders.exe and I don't have a huge choice 
of winderz stuff installed.  So whats it need in addition to a licence 
file I haven't purchased yet. That can always be a showstopper.  That, 
and winders stuff seems to give me a rash...

So thank you Marcus.


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] Printer working, need involute gear designer

[Gene Heskett]

On Thursday 18 June 2020 17:24:56 N wrote:

> If remember correctly something about involute gear used in a gear
> pump, you need the equation for the geometry?
Not at the moment Nick.  I think I solved that problem with a teeny peristaltic 
pump and a couple of timers rigged to be variable excitation for a mister.

Now I'm in the plotting stage of motorizing a BS-1 clone. Mounting a motor on 
the rear with a belt drive to the center of the tilt axis, then a gear from 
there to the worm.  And I don't even have the idler shaft for the middle of the 
tilt axis made yet, nor have I drilled and tapped that hole in the side of it 
yet.  Waiting on more ats-667's, which I got today.

But with the woof in the shop, I need to organize getting her 401-k 
disbursement going to pay the shop bill till whenever...  End stage COPD. And 
I'm running on a 31% pump so I'm not as fast as you younger whippersnappers.  
Darn it.
.
> > Greeting all;
> >
> > 3d Printer is working and actually making solid parts, now I need to
> > make a couple gears. with enough muscle to drive this BS-1 clone.
> >
> > There's a parametric gear thing I have but its a sample of many gear
> > styles and I don't know how to cut it apart and use just the
> > external spur piece of it. I need something that openscad can
> > handle.  But there must be 1000 or more. Most proprietary so are
> > non-starters.
> >
> > Thanks 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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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] Printer working, need involute gear designer

[marcus . bowman]

Gene,

Have you looked at www.gearotic.com
or did someone mention that already?

Marcus


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Re: [Emc-users] Printer working, need involute gear designer

[N]

If remember correctly something about involute gear used in a gear pump, you 
need the equation for the geometry?

> Greeting all;
> 
> 3d Printer is working and actually making solid parts, now I need to make 
> a couple gears. with enough muscle to drive this BS-1 clone.
> 
> There's a parametric gear thing I have but its a sample of many gear 
> styles and I don't know how to cut it apart and use just the external 
> spur piece of it. I need something that openscad can handle.  But there 
> must be 1000 or more. Most proprietary so are non-starters.
> 
> Thanks 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] Universal spindle speed control for $7

[andy pugh]

On Thu, 18 Jun 2020 at 19:40, Chris Albertson  wrote:

>- The angle of the servo shaft is controlled by a PWM signal.

Mesa has a special PWM module intended for controlling these.

-- 
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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[Emc-users] Universal spindle speed control for $7

[Chris Albertson]

I'm making good progress on my 3D printed CNC conversion.  I found a way to
3D print a spindle controller that should work for most small milling
machines and small lathes.   The cost is "almost nothing".   These
machines' spindles are controlled by turning a potentiometer so my new
system simply uses a cheap model airplane servo to turn the shaft of a
potentiometer.  The computer is 100% isolated from any high voltage or
noise.

These small mills will never be able to do things like rigid tapping so all
they need is a simple and approximate way to control the RPM.  This speed
control can be run "open loop" if plus/minus 20% is good enough or used
with a spindle encoder in a closed PID loop as long as the PID is
tunned not to aggressively.


For anyone who does not know about these hobby servos:

   - They are not full rotation motors.  They turn only through about 250
   degrees, This is a good match to the pot as pots also rotate about this
   range.
   - The angle of the servo shaft is controlled by a PWM signal.
   - They are "dirt cheap" starting at about $5 amazon.com/4-Pack-MG996R
   

   - They accept a 5-volt control signal, so they have a built-in computer
   interface.
   - They are fast (enough) and can move from full-low to full-high on 0.6
   seconds
   - They really are actual "servos" and have an encoder, motor driver, and
   gears all inside.


So when LinuxCNC outputs a low-value PWM spindle control, the servo moves
the pot to the low position.  As the PWM signal value gets larger the pot
is moved closer to the high-speed position.

In the picture below is a cartoonish render.  The green frame is one-piece
3D printed,  The red pannel and tan coupler are also 3D printed.  The motor
sells on Amazon, four units for $20 and the pot is about a buck each.  Four
M4 button head screws everything together.

Here is a link to the current version CAD files and a viewer.   I'll be
updating the files after the first prototype is printed.
https://a360.co/2N95AiL
I may make a top cover to protect the pot and keep fingers off the high
voltage.



[image: Red Neck Spindle Control v6.jpg]



-- 

Chris Albertson
Redondo Beach, California
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Re: [Emc-users] Printer working, need involute gear designer

[andy pugh]

On Thu, 18 Jun 2020 at 06:43, Gregg Eshelman via Emc-users
 wrote:
>
>  It's Metric gearing's version of 14 DP, for which you don't want to have to 
> come up with replacement gears.

I can make 14DP gears.  (https://youtu.be/xdE46yvckbM)

-- 
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] Printer working, need involute gear designer

[andy pugh]

On Thu, 18 Jun 2020 at 07:35, Chris Albertson  wrote:
>
> In the US, the traditional system uses teeth per inch.

The Inch version of Module is not circular pitch, it is DP, Diametral Pitch.

And the calculations are just as easy in that system, you just divide
rather than multiply.

In your example, if you had two 30T gears at 4DP then the centre to
centre distance is 30T / 4in, ie 7.5in.

-- 
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] Printer working, need involute gear designer

[Gene Heskett]

On Thursday 18 June 2020 02:32:24 Chris Albertson wrote:

> In the US, the traditional system uses teeth per inch. but the problem
> with this system is "where do you place the tape measure?"  The answer
> is NOT around the outside of the gear.   You need to place the tape
> such that it runs inside the teeth. this is hard to do.  Also here is
> a quiz:You have two gears both 4 "pitch" both are 30 teeth, what
> is the center to center distance?   Can you figure this out in your
> head quickly? I bet not.
>
> Outside the US everyone uses a simple system.  They define "diameter"
> as if the gear were a smooth roller.  So two gears with 40mm diameter
> would have a 40mm center to center distance.  Then they define
> "module" as teeth size that mesh.  so any mod 1.0 gear meshes with any
> mod 1.0 gear.  A mod 0.2 gear meshes with other mod 0.2 gears.
>
> Then and here is the key... "module is the diameter divided by the
> number of teeth"
>
> Example
> (1)   A 40 tooth 40mm diameter gear is module 1.0  it meshes with a
> 20T 20mm diameter gear and the center to center is obviously 20+10=30
> (2) I just printed a Mod. 2.0 gear with 100 teeth. How big is it?  
> Well, some algebra:  2.0 = D/100  So D=200.  It is about 200mm across.
> it is HUGE and covers up most of the build plate on my printer.  The
> mating gear is 25T and you can easily work out the shaft distances
> without the need of a table.
>
> In real life most designs use even number modules like 0.5, 1 or 2.0
> so there are only a handfull of sizes and you learn to identify them
> by sight.
>
> So what is the "pitch" of a mod 1.0 gear?  assume 10T and 10mm
> diameter. The circumstance is 10*pi = 31.4159 mm with 10 teeth the
> pitch is "Pi millimeters" for Mod one.   For mod 2 the pitch is two Pi
> mm and so on.
>
> You don't need a calculator to design stuff with metric gears.
>
> Today there exist countless US standard gears but I can't imagine
> anyone using them in new designs.  Even in the US, the industry is so
> globalized that everyone has switched over.
>
>
>
>
> On Wed, Jun 17, 2020 at 10:43 PM Gregg Eshelman via Emc-users <
>
> emc-users@lists.sourceforge.net> wrote:
> > Module is the Metric version of gear pitch. A google for module gear
> > chart will tell you everything you need to know. There are also
> > module <> diametral pitch converters online in case you're using
> > gear design software that only does Mod or DP but does allow input
> > of arbitrary numbers.
> >
> > My you never ever encounter metric machinery with Mod 2.5 gears.
> > It's Metric gearing's version of 14 DP, for which you don't want to
> > have to come up with replacement gears.

Excellent tut. Makes perfect sense.  Thank you Chris.  

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] Printer working, need involute gear designer

[Chris Albertson]

In the US, the traditional system uses teeth per inch. but the problem with
this system is "where do you place the tape measure?"  The answer is NOT
around the outside of the gear.   You need to place the tape such that it
runs inside the teeth. this is hard to do.  Also here is a quiz:You
have two gears both 4 "pitch" both are 30 teeth, what is the center to
center distance?   Can you figure this out in your head quickly? I bet not.

Outside the US everyone uses a simple system.  They define "diameter" as if
the gear were a smooth roller.  So two gears with 40mm diameter would have
a 40mm center to center distance.  Then they define "module" as teeth
size that mesh.  so any mod 1.0 gear meshes with any mod 1.0 gear.  A mod
0.2 gear meshes with other mod 0.2 gears.

Then and here is the key... "module is the diameter divided by the number
of teeth"

Example
(1)   A 40 tooth 40mm diameter gear is module 1.0  it meshes with a 20T
20mm diameter gear and the center to center is obviously 20+10=30
(2) I just printed a Mod. 2.0 gear with 100 teeth. How big is it?   Well,
some algebra:  2.0 = D/100  So D=200.  It is about 200mm across. it is HUGE
and covers up most of the build plate on my printer.  The mating gear is
25T and you can easily work out the shaft distances without the need of a
table.

In real life most designs use even number modules like 0.5, 1 or 2.0 so
there are only a handfull of sizes and you learn to identify them by sight.

So what is the "pitch" of a mod 1.0 gear?  assume 10T and 10mm diameter.
The circumstance is 10*pi = 31.4159 mm with 10 teeth the pitch is "Pi
millimeters" for Mod one.   For mod 2 the pitch is two Pi mm and so on.

You don't need a calculator to design stuff with metric gears.

Today there exist countless US standard gears but I can't imagine
anyone using them in new designs.  Even in the US, the industry is so
globalized that everyone has switched over.




On Wed, Jun 17, 2020 at 10:43 PM Gregg Eshelman via Emc-users <
emc-users@lists.sourceforge.net> wrote:

> Module is the Metric version of gear pitch. A google for module gear chart
> will tell you everything you need to know. There are also module <>
> diametral pitch converters online in case you're using gear design software
> that only does Mod or DP but does allow input of arbitrary numbers.
>
> My you never ever encounter metric machinery with Mod 2.5 gears. It's
> Metric gearing's version of 14 DP, for which you don't want to have to come
> up with replacement gears.
>
> On Wednesday, June 17, 2020, 9:45:33 PM MDT, Gene Heskett <
> ghesk...@shentel.net> wrote:
>  On Wednesday 17 June 2020 22:23:23 Chris Albertson wrote:
>
>
> > About printed gears.  One thing, just don't try for smaller than
> > about module 1.0.  Yes, 0.5 will mesh but the error in shape is high
> > as they get smaller.
>
> Module is a term I've never met in that context. Where can I find a
> tutorial on it as applied to gears?
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-- 

Chris Albertson
Redondo Beach, California

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