Re: [Emc-users] experimental bearings for harmonic drive

[Gregg Eshelman via Emc-users]

Use a ball cage that snaps in. I designed an example that uses 12 steel BBs.
 
https://www.thingiverse.com/thing:1769802
Bearings are made with the parts sized so that when the inner race is shifted 
as far to one side as it can, the gap on the opposite side is just wide enough 
to insert the balls. When as many balls as can be are put in, the balls are 
distributed around as the inner race is moved to the center. Then either a one 
piece plastic cage is snapped in from one side or a two piece metal cage is 
riveted or spot welded between the balls.


On Monday, March 29, 2021, 8:56:37 AM MDT, Gene Heskett 
 wrote:  
 
 On Sunday 28 March 2021 22:51:17 Gene Heskett wrote:

> On Sunday 28 March 2021 21:00:56 Chris Albertson wrote:
> > Back to printing ball bearings.  The best way is not to do it.  Buy
> > sealed bearing units and press them into a printed recess.  But
> > large diameter sealed bearings can be expensive.    The next best
> > design is to buy metal balls and print the races and assemble them. 
> >  Printing the rollers never works well.  If you want everything to
> > be made of plastic buy the plastic balls used by "airsoft" guns. 
> > These make pretty good bearings, much better than you can print and
> > 2,000 balls, 6mm in diameter cost only $10.
> >
That is an enticing thought, but that will require and entrance notch in 
one side if the races, possibly slightly smaller than the balls since 
the plastic can be stretched a bit to insert the balls. But 6mm is about 
the size of these rollers. and as I play with openscad, I think I just 
found the problem with the rollers vs printing them. The rollers are 
shorter than the races, so the first layer of the rollers is NOT on the 
glass, but .5mm up in the air! Fixed that by reduceing that clearance 
offset to zero. Looks a hell of a lot more printable now. And by the 
time I fined up the rendering to make the straight line facets never 
mind small, its takeing openscad around 5 minutes to render a change.
cura doesn't slice it that fast either. But cura uses all 6 cores of this 
i5, where openscad is single threaded, jumping from core to core as is 
spreads the heat around.

I also found that once wire frameing the view is enabled it can't be 
turned off, but it also a good indicator of how many facets are in the 
circles as rendered.  And if print_view is 0 at the top of this design, 
it only renders 3/4 of a circle so you can look into the end and see all 
the clearances. Sorta like an xray view. Nice for fine tuning this 
design.

And I may have found a bug in cura 4.8.0, or a setting that needs 
changed, it is not rendering the rollers as a solid, but with a filler 
hole down the center that renders the roller very weak in the center 
area. Openscad hands it to cura as a solid, cura make a hole filled with 
infill, and its the same diameter from end to end of the roller.  So I 
need to fix that if I can. What does cura do when walls are thick enough 
to kill the infill?

I have some foot square sheets of that PEI Andy mentioned, and I have 2 
hardened steel .4 nozzles for it coming from microswiss via amazon, 
seems burning out the blockage of the brass dremel nozzle did something 
to it, so since I now know how to change it w/o returning the machine to 
dremel in WI. If the stuff coming doesn't make it print, then I'll do 
just the races in openscad to use the airsoft bb's. I think I can do 
those in openscad reasonably quick.

> > If you like a challenge, try printing a sealed ball bearing unit on
> > one "go".  It can be done as a stint but does not make a good
> > bearing for use in a machine.

I think you meant "stunt". But I am counting on the stretch of the inner 
race when installed over the outside of the moving spline to take up 
some the clearance, and some compression of the outer race when 
installed in an alu output shaft with a ring of alu about 1/4" thick 
around it, both intended to take up some of the clearances rendered.
By making the rollers bigger, tis code is thinning the inner and outer 
races, and I'm still tweeking that. Thinner, to a point, will be better 
as long as the centering guide rings have sufficient support. I'll send 
you a pix of the magnified end view when I'm actually getting a 
printable output.

> > As for getting plastic to stick to glass try cleaning it very well
> > with "Bar Keepers Friend". The stuff is a powder like "Comet" but is
> > acidic and is much better for removing oils and such from
> > fingerprints.  Hairspray usually works too.

My now departed Dee had some, leftovers from her school teaching years, 
but I didn't find it effective at PETG temps. It was quite old but one 
can of it still had some propellant left.

Thanks 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. 

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
>>>
>>>
>>>
>>>
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>>>
>>

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Re: [Emc-users] Small PC for use with 7i90 / 7i96?

[Gene Heskett]

On Monday 29 March 2021 21:59:11 Jon Elson wrote:

> On 03/29/2021 07:48 PM, Billy Huddleston wrote:
> For really small, like a 7" cube, you can get mini ITX
> motherboards and a matching cabinet and power supply from
> the usual outfits like NewEgg, etc.  The 7" cube box allows
> full-height PCI cards.
>
> If you can handle something a little bigger, you can get
> off-lease Dell SFF (Small Form Factor) or Mini-Tower
> computers from the Optiplex (commercial) line quite cheap.
> Put in a small SSD and it makes a quite good machine
> controller.  I've been using the Optiplexes for years with
> excellent results.
>
> Jon
>
I'll second the Optiplex. The later i5 powered ones are giving me very 
low latency-test results, typically 3.5 u-secs, where lower is better. 
Solid, dependable and fast, and you don't have to pick any 2, its all in 
one relatively heavy box.

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] Small PC for use with 7i90 / 7i96?

[Jon Elson]

On 03/29/2021 07:48 PM, Billy Huddleston wrote:
For really small, like a 7" cube, you can get mini ITX 
motherboards and a matching cabinet and power supply from 
the usual outfits like NewEgg, etc.  The 7" cube box allows 
full-height PCI cards.


If you can handle something a little bigger, you can get 
off-lease Dell SFF (Small Form Factor) or Mini-Tower 
computers from the Optiplex (commercial) line quite cheap.  
Put in a small SSD and it makes a quite good machine 
controller.  I've been using the Optiplexes for years with 
excellent results.


Jon


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Re: [Emc-users] Small PC for use with 7i90 / 7i96?

[Billy Huddleston]

The one from Amazon uses a M.2 SATA SSD..  Not a SD Card..

On 3/29/21 8:33 PM, Chris Albertson wrote:

For about the same price you get a real-PC that is much faster that uses an
SSD rather than a memory card for storage.   It is still pretty small
https://www.newegg.com/compaq-6200-student-home-office/p/1VK-001E-3WR47

On Mon, Mar 29, 2021 at 11:51 AM Billy Huddleston  wrote:


Looking for a small form factor PC to use.  Been a while since I've put
together a new system.

Contemplating this: https://www.amazon.com/dp/B085RZDVL5  (Has WiFi for
LAN connection and onboard Ethernet for the MESA Card)

Or perhaps a Intel NUC?  Anyone have suggestions?

--
Billy Huddleston Inner Vision

*William Huddleston
Inner Vision Development*
Office: 865.560.2752
Fax: 865.560.2703

http://www.ivdc.com 
*Development and Consulting... Simplified.*

 
 


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Re: [Emc-users] Small PC for use with 7i90 / 7i96?

[Chris Albertson]

For about the same price you get a real-PC that is much faster that uses an
SSD rather than a memory card for storage.   It is still pretty small
https://www.newegg.com/compaq-6200-student-home-office/p/1VK-001E-3WR47

On Mon, Mar 29, 2021 at 11:51 AM Billy Huddleston  wrote:

> Looking for a small form factor PC to use.  Been a while since I've put
> together a new system.
>
> Contemplating this: https://www.amazon.com/dp/B085RZDVL5  (Has WiFi for
> LAN connection and onboard Ethernet for the MESA Card)
>
> Or perhaps a Intel NUC?  Anyone have suggestions?

-- 

Chris Albertson
Redondo Beach, California

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Re: [Emc-users] Small PC for use with 7i90 / 7i96?

[Gene Heskett]

On Monday 29 March 2021 18:42:00 Billy Huddleston wrote:

> Doesn't have to be the size of a Rpi4. One about the size I posted, or
> a NUC is fine.  I'm even fine with something a bit larger.  I was just
> wondering what was the nominal choice these days. Also, this is for a
> friend, so, I don't want to muck around with a Rpi4 right now.  Need
> it as simple as possible.
>
> Thanks, Billy
>
> On 3/29/21 6:13 PM, Gene Heskett wrote:
> > On Monday 29 March 2021 14:30:19 Billy Huddleston wrote:
> >> Looking for a small form factor PC to use.  Been a while since I've
> >> put together a new system.
> >>
> >> Contemplating this: https://www.amazon.com/dp/B085RZDVL5  (Has WiFi
> >> for LAN connection and onboard Ethernet for the MESA Card)
> >>
> >> Or perhaps a Intel NUC?  Anyone have suggestions?  What's everyone
> >> using these days?
> >>
> >> Thanks, Billy
> >
I just had one of my ark boxes die, it was about 10 years old.  So I went 
to PCLiquidaters and bought a 4 pack of old Dells with 4 core i5's rated 
at 3HGz. With 4GB of dram, and bare hard drives, about $150 a copy. Big, 
I'm having fun fitting them where the shoeboxes were but quicker than 
stink.  And being Dells, about 20 lbs heavier than the ark shoeboxes. 

Installed on bare 240GB SSD drives with our latest iso from linuxcnc.org, 
they just work to whatever interface was there before as I just copied 
the /home/me/linuxcnc directory contents from the old drive to the new 
install, then switched the /etc/atp/sources.d/linuxcnc.list file from 
the 2.8.1 repo to the buildbot and reloaded master.  You can do that 
last anytime. 2.8.1 runs well and is stable.

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] Small PC for use with 7i90 / 7i96?

[Billy Huddleston]

Doesn't have to be the size of a Rpi4. One about the size I posted, or a NUC is fine.  I'm even fine with something a bit larger.  I was just wondering what was the nominal choice 
these days. Also, this is for a friend, so, I don't want to muck around with a Rpi4 right now.  Need it as simple as possible.


Thanks, Billy

On 3/29/21 6:13 PM, Gene Heskett wrote:

On Monday 29 March 2021 14:30:19 Billy Huddleston wrote:


Looking for a small form factor PC to use.  Been a while since I've
put together a new system.

Contemplating this: https://www.amazon.com/dp/B085RZDVL5  (Has WiFi
for LAN connection and onboard Ethernet for the MESA Card)

Or perhaps a Intel NUC?  Anyone have suggestions?  What's everyone
using these days?

Thanks, Billy

I am running an 11x54 Sheldon with a rpi4 with 2 gigs of dram, a mesa
7i90HD and a trio of 7i42TA's. Plus a spinx-1 to run the vfd controlling
an old old 1 horse 3 phase motor. Using a kernel I built.

I also have a couple SSD's on the pi4's usb3 ports, and am running my own
version of a buildbot but its not automatic, rebuilding master on the
pi, for the pi, whenever a git pull generates a mail telling me there's
been a commit to master. 5 to 10 builds a week. To see that code, goto
the link in my sig, then add buildbot-repo to the address line.  Its
complex, read the README which contains a blow by blow of what you have
to do to a stock armhf raspbian buster iso installed on a 64GB u-sd
card. You can get the kernel I'm running, plus the uspace, armhf
versions of linuxcnc I built earlier today there.

Have fun Billy, although you might need some aspirin too.

Cheers, Gene Heskett

--
Billy Huddleston Inner Vision

*William Huddleston
Inner Vision Development*
Office: 865.560.2752
Fax: 865.560.2703

http://www.ivdc.com 
*Development and Consulting... Simplified.*

 
 


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Re: [Emc-users] experimental bearings for harmonic drive

[Gene Heskett]

On Monday 29 March 2021 16:07:22 Frank Tkalcevic wrote:

> > That is an enticing thought, but that will require and entrance
> > notch in one side if the races
>
> This is an example of not having to put a filling notch in your
> bearings - https://youtu.be/3-Jcp8vFAko?t=41
>
> There are not enough balls to reach all the way around, so they can be
> easily loaded, but are then held in place with a cage (I'm guessing
> that's how sealed units are made).
>
Probably.I've seen them with and without, Frank. Those w/o have fewer 
bearings.

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] Small PC for use with 7i90 / 7i96?

[Gene Heskett]

On Monday 29 March 2021 14:30:19 Billy Huddleston wrote:

> Looking for a small form factor PC to use.  Been a while since I've
> put together a new system.
>
> Contemplating this: https://www.amazon.com/dp/B085RZDVL5  (Has WiFi
> for LAN connection and onboard Ethernet for the MESA Card)
>
> Or perhaps a Intel NUC?  Anyone have suggestions?  What's everyone
> using these days?
>
> Thanks, Billy

I am running an 11x54 Sheldon with a rpi4 with 2 gigs of dram, a mesa 
7i90HD and a trio of 7i42TA's. Plus a spinx-1 to run the vfd controlling 
an old old 1 horse 3 phase motor. Using a kernel I built.

I also have a couple SSD's on the pi4's usb3 ports, and am running my own 
version of a buildbot but its not automatic, rebuilding master on the 
pi, for the pi, whenever a git pull generates a mail telling me there's 
been a commit to master. 5 to 10 builds a week. To see that code, goto 
the link in my sig, then add buildbot-repo to the address line.  Its 
complex, read the README which contains a blow by blow of what you have 
to do to a stock armhf raspbian buster iso installed on a 64GB u-sd 
card. You can get the kernel I'm running, plus the uspace, armhf 
versions of linuxcnc I built earlier today there.

Have fun Billy, although you might need some aspirin too.

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] Small PC for use with 7i90 / 7i96?

[andy pugh]

On Mon, 29 Mar 2021 at 19:51, Billy Huddleston  wrote:

> Contemplating this: https://www.amazon.com/dp/B085RZDVL5

I have one of the previous model, it works perfectly adequately.
In fact I bought it specifically to test the LinuxCNC installer on
UEFI hadware, so I am pretty confident that LinuxCNC will install on
it.

I did have some trouble with the WiFi system, but I seem to have got
it working now.
(On the wired network, use Synaptic to install network-manager and
nm-tray. That seemed to "just work" in ways that wicd just didn't.
I _might_ have had to follow the instructions in this post, but that
might also have been unnecessary:
https://forums.linuxmint.com/viewtopic.php?p=1589492#p1589492 )

-- 
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] experimental bearings for harmonic drive

[Gene Heskett]

On Monday 29 March 2021 11:24:18 andy pugh wrote:

> On Mon, 29 Mar 2021 at 01:26, Gene Heskett  
wrote:
> > Thats not what I have, and DDG searching for PEI gets you about the
> > first 500 hits for Prince Edward Island. :)
>
> Try eBay and "PEI Printing Surface"

I didn't quite hit that but I found foot square sheets with adhesive at 
gizmodorks and have 2 sheets coming. The dremel has a non square work 
glass a bit larger than 5.5 x10 inches. So to get that 10.375" I have to 
buy foot squares, but the price at gizmodorks wasn't that outrageous.

Since I have come to the conclusion I damaged the nozzle by burning out 
the obstruction, I've bought two hardened, plated steel nozzles from 
microswiss that are claimed to fit the dremel.  We'll see when they 
arrive. In the meantime, I've found why the first layer of the rollers 
came off the glass, they were shorter than the races so the printer was 
trying to lay then up in the air 2 or 3 layers off the glass. Fixed, 
gonna make breakfast and start another test print.
==
I have since started it 6 or so times, finally getting a usable head gap, 
now scaling the flow down trying to keep it from slobbering, leaving a 
blob on top of a dot, then busting a dot loose and sticking it to the 
nozzle, which then wipes out the rest of the roller dots as it come to 
put the 2nd or third layer on them.  These patches to make cura run a 
digilab aren't claimed to be optimized, and I hearby nominate that for 
understatement of the year.

Qestion, nearly to the bottom of the config options for cura, is a flow 
statement that sorta reads like it might scale all the rest of the flow 
settings in one swell foop, called "Flow rate compensation factor".

Can anyone confirm that it is a global setting? 

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] experimental bearings for harmonic drive

[Frank Tkalcevic]

> That is an enticing thought, but that will require and entrance notch in 
> one side if the races

This is an example of not having to put a filling notch in your bearings -
https://youtu.be/3-Jcp8vFAko?t=41

There are not enough balls to reach all the way around, so they can be
easily loaded, but are then held in place with a cage (I'm guessing that's
how sealed units are made).



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[Emc-users] Small PC for use with 7i90 / 7i96?

[Billy Huddleston]

Looking for a small form factor PC to use.  Been a while since I've put 
together a new system.

Contemplating this: https://www.amazon.com/dp/B085RZDVL5  (Has WiFi for LAN 
connection and onboard Ethernet for the MESA Card)

Or perhaps a Intel NUC?  Anyone have suggestions?  What's everyone using these 
days?

Thanks, Billy
--

Billy Huddleston Inner Vision

*
*


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Re: [Emc-users] experimental bearings for harmonic drive

[andy pugh]

On Mon, 29 Mar 2021 at 01:26, Gene Heskett  wrote:

> Thats not what I have, and DDG searching for PEI gets you about the first
> 500 hits for Prince Edward Island. :)

Try eBay and "PEI Printing Surface"

-- 
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] experimental bearings for harmonic drive

[Gene Heskett]

On Sunday 28 March 2021 22:51:17 Gene Heskett wrote:

> On Sunday 28 March 2021 21:00:56 Chris Albertson wrote:
> > Back to printing ball bearings.   The best way is not to do it.  Buy
> > sealed bearing units and press them into a printed recess.   But
> > large diameter sealed bearings can be expensive.The next best
> > design is to buy metal balls and print the races and assemble them. 
> >  Printing the rollers never works well.  If you want everything to
> > be made of plastic buy the plastic balls used by "airsoft" guns. 
> > These make pretty good bearings, much better than you can print and
> > 2,000 balls, 6mm in diameter cost only $10.
> >
That is an enticing thought, but that will require and entrance notch in 
one side if the races, possibly slightly smaller than the balls since 
the plastic can be stretched a bit to insert the balls. But 6mm is about 
the size of these rollers. and as I play with openscad, I think I just 
found the problem with the rollers vs printing them. The rollers are 
shorter than the races, so the first layer of the rollers is NOT on the 
glass, but .5mm up in the air! Fixed that by reduceing that clearance 
offset to zero. Looks a hell of a lot more printable now. And by the 
time I fined up the rendering to make the straight line facets never 
mind small, its takeing openscad around 5 minutes to render a change.
cura doesn't slice it that fast either. But cura uses all 6 cores of this 
i5, where openscad is single threaded, jumping from core to core as is 
spreads the heat around.

I also found that once wire frameing the view is enabled it can't be 
turned off, but it also a good indicator of how many facets are in the 
circles as rendered.  And if print_view is 0 at the top of this design, 
it only renders 3/4 of a circle so you can look into the end and see all 
the clearances. Sorta like an xray view. Nice for fine tuning this 
design.

And I may have found a bug in cura 4.8.0, or a setting that needs 
changed, it is not rendering the rollers as a solid, but with a filler 
hole down the center that renders the roller very weak in the center 
area. Openscad hands it to cura as a solid, cura make a hole filled with 
infill, and its the same diameter from end to end of the roller.  So I 
need to fix that if I can. What does cura do when walls are thick enough 
to kill the infill?

I have some foot square sheets of that PEI Andy mentioned, and I have 2 
hardened steel .4 nozzles for it coming from microswiss via amazon, 
seems burning out the blockage of the brass dremel nozzle did something 
to it, so since I now know how to change it w/o returning the machine to 
dremel in WI. If the stuff coming doesn't make it print, then I'll do 
just the races in openscad to use the airsoft bb's. I think I can do 
those in openscad reasonably quick.

> > If you like a challenge, try printing a sealed ball bearing unit on
> > one "go".  It can be done as a stint but does not make a good
> > bearing for use in a machine.

I think you meant "stunt". But I am counting on the stretch of the inner 
race when installed over the outside of the moving spline to take up 
some the clearance, and some compression of the outer race when 
installed in an alu output shaft with a ring of alu about 1/4" thick 
around it, both intended to take up some of the clearances rendered.
By making the rollers bigger, tis code is thinning the inner and outer 
races, and I'm still tweeking that. Thinner, to a point, will be better 
as long as the centering guide rings have sufficient support. I'll send 
you a pix of the magnified end view when I'm actually getting a 
printable output.

> > As for getting plastic to stick to glass try cleaning it very well
> > with "Bar Keepers Friend". The stuff is a powder like "Comet" but is
> > acidic and is much better for removing oils and such from
> > fingerprints.   Hairspray usually works too.

My now departed Dee had some, leftovers from her school teaching years, 
but I didn't find it effective at PETG temps. It was quite old but one 
can of it still had some propellant left.

Thanks 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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