Re: [Emc-users] SPAM: Re: precisiomn indexer

[Gene Heskett]

On Friday 28 August 2020 21:53:50 Greg Bernard wrote:

> Have you considered having the flex gear part printed by one of the 3d
> printing services in nylon? You could then print all the other parts
> yourself to fit. Most of the services can give you a quote if you send
> a file.

I'm about 1mm from having te 3rd one I need completed. Then I might need 
to epoxy or superglue the bearing carrier to the motor shaft. That was 
also a weak spot in the design.
>
> On Fri, Aug 28, 2020, 4:55 PM Gene Heskett  
wrote:
> > On Friday 28 August 2020 16:04:11 Chris Albertson wrote:
> > > Gene,
> > >
> > > I thought you had the STEP file for this.   If you did not
> > > download it, I did and you can have my copy of it here
> > > https://a360.co/2EHlpMr
> >
> > I do have it, but opening it with the latest freecad, does not get
> > me down into it to modify it.
> >
> > > I've been reading about printable harmonic drives and the best
> > > idea I found is to use a stainless steel drinking cup as the flex
> > > cup (after cutting off the rim) and gluing a timing belt to the
> > > cup to make the teeth.   The steel/rubber composite seems to last
> > > a long time.
> >
> > Sounds good, and may work for gear reduction ok, but there would be
> > a huge, high frequency cyclic speed variation due the the shape of
> > the teeth in a timing belt.  And that isn't exactly friendly to
> > guiding a star gazers telescope.  These won't be that great either,
> > but why design in a known flaw?
> >
> > > On Fri, Aug 28, 2020 at 11:37 AM Gene Heskett
> > > 
> >
> > wrote:
> > > > On Friday 28 August 2020 12:36:07 Todd Zuercher wrote:
> > > > > If you think about it the metal toothed cups used in harmonic
> > > > > drives, have to flex in a rather nasty way (it is a little
> > > > > more than just squeezing the mouth into an oval).  I'm
> > > > > surprised they last as long as they do. I'm not surprised you
> > > > > are having cracking problems with the pla.  What is the
> > > > > distance from where the cup is pinched by the bearing to the
> > > > > face of the cup? Increasing that distance should improve the
> > > > > durability.  Also I think I would slightly increase the
> > > > > thickness and add a slight fillet to the inside transitioning
> > > > > from the wall to the cup face.  Then taper the cup wall down
> > > > > and have it be it's thinnest (probably thinner than you have
> > > > > it now) for the majority of the height of the cup then thicken
> > > > > it again to accommodate the toothed surface at the bottom.
> > > >
> > > > I don't have the original src, just the stl's that the slicer
> > > > can make g-code out of. So the limits of my ability to adjust
> > > > such is limited to the xyz scale settings of the printer.
> > > >
> > > > > I do have the remains of a busted commercially made harmonic
> > > > > drive in a box on a shelf.  It was in the tool changer of a
> > > > > used machine we bought.  I don't know how it was originally
> > > > > broken, but it to failed at the transition of wall to face,
> > > > > the previous owner had tried to fix it by welding the cup back
> > > > > together.  It worked for about 6 months after we bought the
> > > > > machine, until the welds fatigued and failed.  In the mean
> > > > > time the part was redesigned by the harmonic drive
> > > > > manufacturer with a much taller cup for the replacement part
> > > > > (also requiring us to replace of a number of other parts in
> > > > > our tool changer to accommodate the redesigned part.)
> > > >
> > > > I fail to grok the reason they used a expensive part like a
> > > > harmonic drive for speed reduction in a tool changer. Boggles
> > > > what little mind I have left at my years.  An eletric wiper
> > > > motor can be made to do that job with adequate accuracy.  Really
> > > > precise location can be had by backing up aganst a pawl. Abuse
> > > > the motor to get the power to move a long chain if needed, its
> > > > not something that has to run 500+ miles non-stop in a blizzard.
> > > > It doesn't run long enough to get hot at any one time unless the
> > > > designer is an idiot.  Oh, wait, I've met some of them. Some
> > > > are.
> > > >
> > > > Stay safe and well Todd.
> > > >
> > > > > Todd Zuercher
> > > > > P. Graham Dunn Inc.
> > > > > 630 Henry Street
> > > > > Dalton, Ohio 44618
> > > > > Phone:  (330)828-2105ext. 2031
> > > > >
> > > > > -Original Message-
> > > > > From: Gene Heskett 
> > > > > Sent: Friday, August 28, 2020 11:10 AM
> > > > > To: emc-users@lists.sourceforge.net
> > > > > Subject: SPAM: Re: [Emc-users] precisiomn indexer
> > > > >
> > > > > [EXTERNAL EMAIL] Be sure links are safe.
> > > > >
> > > > > On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:
> > > > > > Gene an old client called about using a Newbould indexer on
> > > > > > his machine.
> > > > > >
> > > > > > I remember it was a hirth 'gear' or coupler
> > > > > >
> > > > > > Very accurate stacking 'gears' , a way to set a part at
> > 

Re: [Emc-users] SPAM: Re: precisiomn indexer

[Greg Bernard]

Have you considered having the flex gear part printed by one of the 3d
printing services in nylon? You could then print all the other parts
yourself to fit. Most of the services can give you a quote if you send a
file.



On Fri, Aug 28, 2020, 4:55 PM Gene Heskett  wrote:

> On Friday 28 August 2020 16:04:11 Chris Albertson wrote:
>
> > Gene,
> >
> > I thought you had the STEP file for this.   If you did not download
> > it, I did and you can have my copy of it here
> > https://a360.co/2EHlpMr
> >
> I do have it, but opening it with the latest freecad, does not get me
> down into it to modify it.
>
> > I've been reading about printable harmonic drives and the best idea I
> > found is to use a stainless steel drinking cup as the flex cup (after
> > cutting off the rim) and gluing a timing belt to the cup to make the
> > teeth.   The steel/rubber composite seems to last a long time.
>
> Sounds good, and may work for gear reduction ok, but there would be a
> huge, high frequency cyclic speed variation due the the shape of the
> teeth in a timing belt.  And that isn't exactly friendly to guiding a
> star gazers telescope.  These won't be that great either, but why design
> in a known flaw?
>
> > On Fri, Aug 28, 2020 at 11:37 AM Gene Heskett 
> wrote:
> > > On Friday 28 August 2020 12:36:07 Todd Zuercher wrote:
> > > > If you think about it the metal toothed cups used in harmonic
> > > > drives, have to flex in a rather nasty way (it is a little more
> > > > than just squeezing the mouth into an oval).  I'm surprised they
> > > > last as long as they do. I'm not surprised you are having cracking
> > > > problems with the pla.  What is the distance from where the cup is
> > > > pinched by the bearing to the face of the cup? Increasing that
> > > > distance should improve the durability.  Also I think I would
> > > > slightly increase the thickness and add a slight fillet to the
> > > > inside transitioning from the wall to the cup face.  Then taper
> > > > the cup wall down and have it be it's thinnest (probably thinner
> > > > than you have it now) for the majority of the height of the cup
> > > > then thicken it again to accommodate the toothed surface at the
> > > > bottom.
> > >
> > > I don't have the original src, just the stl's that the slicer can
> > > make g-code out of. So the limits of my ability to adjust such is
> > > limited to the xyz scale settings of the printer.
> > >
> > > > I do have the remains of a busted commercially made harmonic drive
> > > > in a box on a shelf.  It was in the tool changer of a used machine
> > > > we bought.  I don't know how it was originally broken, but it to
> > > > failed at the transition of wall to face, the previous owner had
> > > > tried to fix it by welding the cup back together.  It worked for
> > > > about 6 months after we bought the machine, until the welds
> > > > fatigued and failed.  In the mean time the part was redesigned by
> > > > the harmonic drive manufacturer with a much taller cup for the
> > > > replacement part (also requiring us to replace of a number of
> > > > other parts in our tool changer to accommodate the redesigned
> > > > part.)
> > >
> > > I fail to grok the reason they used a expensive part like a harmonic
> > > drive for speed reduction in a tool changer. Boggles what little
> > > mind I have left at my years.  An eletric wiper motor can be made to
> > > do that job with adequate accuracy.  Really precise location can be
> > > had by backing up aganst a pawl. Abuse the motor to get the power to
> > > move a long chain if needed, its not something that has to run 500+
> > > miles non-stop in a blizzard. It doesn't run long enough to get hot
> > > at any one time unless the designer is an idiot.  Oh, wait, I've met
> > > some of them. Some are.
> > >
> > > Stay safe and well Todd.
> > >
> > > > Todd Zuercher
> > > > P. Graham Dunn Inc.
> > > > 630 Henry Street
> > > > Dalton, Ohio 44618
> > > > Phone:  (330)828-2105ext. 2031
> > > >
> > > > -Original Message-
> > > > From: Gene Heskett 
> > > > Sent: Friday, August 28, 2020 11:10 AM
> > > > To: emc-users@lists.sourceforge.net
> > > > Subject: SPAM: Re: [Emc-users] precisiomn indexer
> > > >
> > > > [EXTERNAL EMAIL] Be sure links are safe.
> > > >
> > > > On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:
> > > > > Gene an old client called about using a Newbould indexer on his
> > > > > machine.
> > > > >
> > > > > I remember it was a hirth 'gear' or coupler
> > > > >
> > > > > Very accurate stacking 'gears' , a way to set a part at precise
> > > > > angles
> > > > >
> > > > > I thought... "Hey Gene could _print_ one"
> > > > >
> > > > > as if you dont have enough to do :-)
> > > > >
> > > > > just FYI
> > > > >
> > > > > TomP
> > > > >
> > > > > https://en.wikipedia.org/wiki/Hirth_joint
> > > > >
> > > > > https://www.youtube.com/watch?v=3EGGuR5YziE
> > > >
> > > > The odd tooth version could probably be done in sub-degree jumps
> > > > but not with a 3d printers 

Re: [Emc-users] SPAM: Re: precisiomn indexer

[Gene Heskett]

On Friday 28 August 2020 16:04:11 Chris Albertson wrote:

> Gene,
>
> I thought you had the STEP file for this.   If you did not download
> it, I did and you can have my copy of it here
> https://a360.co/2EHlpMr
>
I do have it, but opening it with the latest freecad, does not get me 
down into it to modify it.

> I've been reading about printable harmonic drives and the best idea I
> found is to use a stainless steel drinking cup as the flex cup (after
> cutting off the rim) and gluing a timing belt to the cup to make the
> teeth.   The steel/rubber composite seems to last a long time.

Sounds good, and may work for gear reduction ok, but there would be a 
huge, high frequency cyclic speed variation due the the shape of the 
teeth in a timing belt.  And that isn't exactly friendly to guiding a 
star gazers telescope.  These won't be that great either, but why design 
in a known flaw?

> On Fri, Aug 28, 2020 at 11:37 AM Gene Heskett  
wrote:
> > On Friday 28 August 2020 12:36:07 Todd Zuercher wrote:
> > > If you think about it the metal toothed cups used in harmonic
> > > drives, have to flex in a rather nasty way (it is a little more
> > > than just squeezing the mouth into an oval).  I'm surprised they
> > > last as long as they do. I'm not surprised you are having cracking
> > > problems with the pla.  What is the distance from where the cup is
> > > pinched by the bearing to the face of the cup? Increasing that
> > > distance should improve the durability.  Also I think I would
> > > slightly increase the thickness and add a slight fillet to the
> > > inside transitioning from the wall to the cup face.  Then taper
> > > the cup wall down and have it be it's thinnest (probably thinner
> > > than you have it now) for the majority of the height of the cup
> > > then thicken it again to accommodate the toothed surface at the
> > > bottom.
> >
> > I don't have the original src, just the stl's that the slicer can
> > make g-code out of. So the limits of my ability to adjust such is
> > limited to the xyz scale settings of the printer.
> >
> > > I do have the remains of a busted commercially made harmonic drive
> > > in a box on a shelf.  It was in the tool changer of a used machine
> > > we bought.  I don't know how it was originally broken, but it to
> > > failed at the transition of wall to face, the previous owner had
> > > tried to fix it by welding the cup back together.  It worked for
> > > about 6 months after we bought the machine, until the welds
> > > fatigued and failed.  In the mean time the part was redesigned by
> > > the harmonic drive manufacturer with a much taller cup for the
> > > replacement part (also requiring us to replace of a number of
> > > other parts in our tool changer to accommodate the redesigned
> > > part.)
> >
> > I fail to grok the reason they used a expensive part like a harmonic
> > drive for speed reduction in a tool changer. Boggles what little
> > mind I have left at my years.  An eletric wiper motor can be made to
> > do that job with adequate accuracy.  Really precise location can be
> > had by backing up aganst a pawl. Abuse the motor to get the power to
> > move a long chain if needed, its not something that has to run 500+
> > miles non-stop in a blizzard. It doesn't run long enough to get hot
> > at any one time unless the designer is an idiot.  Oh, wait, I've met
> > some of them. Some are.
> >
> > Stay safe and well Todd.
> >
> > > Todd Zuercher
> > > P. Graham Dunn Inc.
> > > 630 Henry Street
> > > Dalton, Ohio 44618
> > > Phone:  (330)828-2105ext. 2031
> > >
> > > -Original Message-
> > > From: Gene Heskett 
> > > Sent: Friday, August 28, 2020 11:10 AM
> > > To: emc-users@lists.sourceforge.net
> > > Subject: SPAM: Re: [Emc-users] precisiomn indexer
> > >
> > > [EXTERNAL EMAIL] Be sure links are safe.
> > >
> > > On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:
> > > > Gene an old client called about using a Newbould indexer on his
> > > > machine.
> > > >
> > > > I remember it was a hirth 'gear' or coupler
> > > >
> > > > Very accurate stacking 'gears' , a way to set a part at precise
> > > > angles
> > > >
> > > > I thought... "Hey Gene could _print_ one"
> > > >
> > > > as if you dont have enough to do :-)
> > > >
> > > > just FYI
> > > >
> > > > TomP
> > > >
> > > > https://en.wikipedia.org/wiki/Hirth_joint
> > > >
> > > > https://www.youtube.com/watch?v=3EGGuR5YziE
> > >
> > > The odd tooth version could probably be done in sub-degree jumps
> > > but not with a 3d printers tolerances.
> > >
> > > I'm learning how to make flexgears for a harmonic drive out of
> > > TPU. PLA hasn't enough flex and breaks in less than 5 minutes
> > > running time.
> > >
> > > And I've two that have now run at an output speed of about 1 rev
> > > in 4 seconds for over 24 hours. Unlike the really preciely made
> > > metal one's, it has to have a touch of backlash, but with a decent
> > > driver, and none of the TB series fit that description, because
> > > 

Re: [Emc-users] Gecko 203v

[Jon Elson]

On 08/28/2020 12:59 PM, Dave Pape wrote:

I had a noise problem with the 203v. I solved the problem by re tapping the
4-40 ground screw in the center of the Gecko's black heat sink. The heat
sink is anodized making it non electrically conductive. My 4 Gecko's are
all mounted on one common heat sink, and after making everything grounded
the same, the noise was gone.
Ah HA!  So, the OPPOSITE of my suggestion.  But, makes a lot 
of sense, if a big chunk of aluminum is floating, but 
capacitively coupled to the transistors inside, that could 
cause problems.


Jon


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Re: [Emc-users] SPAM: Re: precisiomn indexer

[Chris Albertson]

Gene,

I thought you had the STEP file for this.   If you did not download it, I
did and you can have my copy of it here
https://a360.co/2EHlpMr

I've been reading about printable harmonic drives and the best idea I found
is to use a stainless steel drinking cup as the flex cup (after cutting off
the rim) and gluing a timing belt to the cup to make the teeth.   The
steel/rubber composite seems to last a long time.

On Fri, Aug 28, 2020 at 11:37 AM Gene Heskett  wrote:

> On Friday 28 August 2020 12:36:07 Todd Zuercher wrote:
>
> > If you think about it the metal toothed cups used in harmonic drives,
> > have to flex in a rather nasty way (it is a little more than just
> > squeezing the mouth into an oval).  I'm surprised they last as long as
> > they do. I'm not surprised you are having cracking problems with the
> > pla.  What is the distance from where the cup is pinched by the
> > bearing to the face of the cup? Increasing that distance should
> > improve the durability.  Also I think I would slightly increase the
> > thickness and add a slight fillet to the inside transitioning from the
> > wall to the cup face.  Then taper the cup wall down and have it be
> > it's thinnest (probably thinner than you have it now) for the majority
> > of the height of the cup then thicken it again to accommodate the
> > toothed surface at the bottom.
>
> I don't have the original src, just the stl's that the slicer can make
> g-code out of. So the limits of my ability to adjust such is limited to
> the xyz scale settings of the printer.
> >
> > I do have the remains of a busted commercially made harmonic drive in
> > a box on a shelf.  It was in the tool changer of a used machine we
> > bought.  I don't know how it was originally broken, but it to failed
> > at the transition of wall to face, the previous owner had tried to fix
> > it by welding the cup back together.  It worked for about 6 months
> > after we bought the machine, until the welds fatigued and failed.  In
> > the mean time the part was redesigned by the harmonic drive
> > manufacturer with a much taller cup for the replacement part (also
> > requiring us to replace of a number of other parts in our tool changer
> > to accommodate the redesigned part.)
> >
> I fail to grok the reason they used a expensive part like a harmonic
> drive for speed reduction in a tool changer. Boggles what little mind I
> have left at my years.  An eletric wiper motor can be made to do that
> job with adequate accuracy.  Really precise location can be had by
> backing up aganst a pawl. Abuse the motor to get the power to move a
> long chain if needed, its not something that has to run 500+ miles
> non-stop in a blizzard. It doesn't run long enough to get hot at any one
> time unless the designer is an idiot.  Oh, wait, I've met some of them.
> Some are.
>
> Stay safe and well Todd.
>
> > Todd Zuercher
> > P. Graham Dunn Inc.
> > 630 Henry Street
> > Dalton, Ohio 44618
> > Phone:  (330)828-2105ext. 2031
> >
> > -Original Message-
> > From: Gene Heskett 
> > Sent: Friday, August 28, 2020 11:10 AM
> > To: emc-users@lists.sourceforge.net
> > Subject: SPAM: Re: [Emc-users] precisiomn indexer
> >
> > [EXTERNAL EMAIL] Be sure links are safe.
> >
> > On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:
> > > Gene an old client called about using a Newbould indexer on his
> > > machine.
> > >
> > > I remember it was a hirth 'gear' or coupler
> > >
> > > Very accurate stacking 'gears' , a way to set a part at precise
> > > angles
> > >
> > > I thought... "Hey Gene could _print_ one"
> > >
> > > as if you dont have enough to do :-)
> > >
> > > just FYI
> > >
> > > TomP
> > >
> > > https://en.wikipedia.org/wiki/Hirth_joint
> > >
> > > https://www.youtube.com/watch?v=3EGGuR5YziE
> >
> > The odd tooth version could probably be done in sub-degree jumps but
> > not with a 3d printers tolerances.
> >
> > I'm learning how to make flexgears for a harmonic drive out of TPU.
> > PLA hasn't enough flex and breaks in less than 5 minutes running time.
> >
> > And I've two that have now run at an output speed of about 1 rev in 4
> > seconds for over 24 hours. Unlike the really preciely made metal
> > one's, it has to have a touch of backlash, but with a decent driver,
> > and none of the TB series fit that description, because they don't
> > auto-throttle the currants, it looks like I'll have enough torque from
> > a nema 17 motor to drive the worm of a clone BS-1, under cutting load
> > no less.
> >
> > TPU can be a cast iron bitch, its 100x more finicky about temps and
> > speeds than PLA.  Currently seems to be working, but at a nozzle temp
> > 15C above whats noted on the no-name box I bought 2 of for a $70 bill.
> > Virtually zero extruder drive grip allowed in a Micro-Swiss hot end
> > that moves the extruder motor to the X carriage.
> >
> > Thanks TomP, stay safe and well, both of you.
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:

[Emc-users] Gecko 203v

[Dave Pape]

I had a noise problem with the 203v. I solved the problem by re tapping the
4-40 ground screw in the center of the Gecko's black heat sink. The heat
sink is anodized making it non electrically conductive. My 4 Gecko's are
all mounted on one common heat sink, and after making everything grounded
the same, the noise was gone. I have US digital encoders on every motor,
and Jon Elson suggested that I put a capacitor on the plus and minus power
input to the encoder chip. The capacitor cleaned up the encoder signal's.
US digital has a new chip that is more noise immune than the chip I used.
I am using Ubuntu 10.04 LTS on my Emco FB2 mill, and LinuxCNC V2.5. The
computer is an Intel Atom D945GCLF 2D. My system has been running for 10
years now just fine.
I hope this helps.

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Re: [Emc-users] SPAM: Re: precisiomn indexer

[Gene Heskett]

On Friday 28 August 2020 12:36:07 Todd Zuercher wrote:

> If you think about it the metal toothed cups used in harmonic drives,
> have to flex in a rather nasty way (it is a little more than just
> squeezing the mouth into an oval).  I'm surprised they last as long as
> they do. I'm not surprised you are having cracking problems with the
> pla.  What is the distance from where the cup is pinched by the
> bearing to the face of the cup? Increasing that distance should
> improve the durability.  Also I think I would slightly increase the
> thickness and add a slight fillet to the inside transitioning from the
> wall to the cup face.  Then taper the cup wall down and have it be
> it's thinnest (probably thinner than you have it now) for the majority
> of the height of the cup then thicken it again to accommodate the
> toothed surface at the bottom.

I don't have the original src, just the stl's that the slicer can make 
g-code out of. So the limits of my ability to adjust such is limited to 
the xyz scale settings of the printer.
>
> I do have the remains of a busted commercially made harmonic drive in
> a box on a shelf.  It was in the tool changer of a used machine we
> bought.  I don't know how it was originally broken, but it to failed
> at the transition of wall to face, the previous owner had tried to fix
> it by welding the cup back together.  It worked for about 6 months
> after we bought the machine, until the welds fatigued and failed.  In
> the mean time the part was redesigned by the harmonic drive
> manufacturer with a much taller cup for the replacement part (also
> requiring us to replace of a number of other parts in our tool changer
> to accommodate the redesigned part.)
>
I fail to grok the reason they used a expensive part like a harmonic 
drive for speed reduction in a tool changer. Boggles what little mind I 
have left at my years.  An eletric wiper motor can be made to do that 
job with adequate accuracy.  Really precise location can be had by 
backing up aganst a pawl. Abuse the motor to get the power to move a 
long chain if needed, its not something that has to run 500+ miles 
non-stop in a blizzard. It doesn't run long enough to get hot at any one 
time unless the designer is an idiot.  Oh, wait, I've met some of them.  
Some are.

Stay safe and well Todd. 

> Todd Zuercher
> P. Graham Dunn Inc.
> 630 Henry Street 
> Dalton, Ohio 44618
> Phone:  (330)828-2105ext. 2031
>
> -Original Message-
> From: Gene Heskett 
> Sent: Friday, August 28, 2020 11:10 AM
> To: emc-users@lists.sourceforge.net
> Subject: SPAM: Re: [Emc-users] precisiomn indexer
>
> [EXTERNAL EMAIL] Be sure links are safe.
>
> On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:
> > Gene an old client called about using a Newbould indexer on his
> > machine.
> >
> > I remember it was a hirth 'gear' or coupler
> >
> > Very accurate stacking 'gears' , a way to set a part at precise
> > angles
> >
> > I thought... "Hey Gene could _print_ one"
> >
> > as if you dont have enough to do :-)
> >
> > just FYI
> >
> > TomP
> >
> > https://en.wikipedia.org/wiki/Hirth_joint
> >
> > https://www.youtube.com/watch?v=3EGGuR5YziE
>
> The odd tooth version could probably be done in sub-degree jumps but
> not with a 3d printers tolerances.
>
> I'm learning how to make flexgears for a harmonic drive out of TPU. 
> PLA hasn't enough flex and breaks in less than 5 minutes running time.
>
> And I've two that have now run at an output speed of about 1 rev in 4
> seconds for over 24 hours. Unlike the really preciely made metal
> one's, it has to have a touch of backlash, but with a decent driver,
> and none of the TB series fit that description, because they don't
> auto-throttle the currants, it looks like I'll have enough torque from
> a nema 17 motor to drive the worm of a clone BS-1, under cutting load
> no less.
>
> TPU can be a cast iron bitch, its 100x more finicky about temps and
> speeds than PLA.  Currently seems to be working, but at a nozzle temp
> 15C above whats noted on the no-name box I bought 2 of for a $70 bill.
> Virtually zero extruder drive grip allowed in a Micro-Swiss hot end
> that moves the extruder motor to the X carriage.
>
> Thanks TomP, stay safe and well, both of you.
>
> 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
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>
>
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Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of 

Re: [Emc-users] SPAM: Re: precisiomn indexer

[Todd Zuercher]

If you think about it the metal toothed cups used in harmonic drives, have to 
flex in a rather nasty way (it is a little more than just squeezing the mouth 
into an oval).  I'm surprised they last as long as they do.
I'm not surprised you are having cracking problems with the pla.  What is the 
distance from where the cup is pinched by the bearing to the face of the cup?
Increasing that distance should improve the durability.  Also I think I would 
slightly increase the thickness and add a slight fillet to the inside 
transitioning from the wall to the cup face.  Then taper the cup wall down and 
have it be it's thinnest (probably thinner than you have it now) for the 
majority of the height of the cup then thicken it again to accommodate the 
toothed surface at the bottom.

I do have the remains of a busted commercially made harmonic drive in a box on 
a shelf.  It was in the tool changer of a used machine we bought.  I don't know 
how it was originally broken, but it to failed at the transition of wall to 
face, the previous owner had tried to fix it by welding the cup back together.  
It worked for about 6 months after we bought the machine, until the welds 
fatigued and failed.  In the mean time the part was redesigned by the harmonic 
drive manufacturer with a much taller cup for the replacement part (also 
requiring us to replace of a number of other parts in our tool changer to 
accommodate the redesigned part.)

Todd Zuercher
P. Graham Dunn Inc.
630 Henry Street 
Dalton, Ohio 44618
Phone:  (330)828-2105ext. 2031

-Original Message-
From: Gene Heskett  
Sent: Friday, August 28, 2020 11:10 AM
To: emc-users@lists.sourceforge.net
Subject: SPAM: Re: [Emc-users] precisiomn indexer

[EXTERNAL EMAIL] Be sure links are safe.

On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:

> Gene an old client called about using a Newbould indexer on his 
> machine.
>
> I remember it was a hirth 'gear' or coupler
>
> Very accurate stacking 'gears' , a way to set a part at precise angles
>
> I thought... "Hey Gene could _print_ one"
>
> as if you dont have enough to do :-)
>
> just FYI
>
> TomP
>
> https://en.wikipedia.org/wiki/Hirth_joint
>
> https://www.youtube.com/watch?v=3EGGuR5YziE
>
The odd tooth version could probably be done in sub-degree jumps but not with a 
3d printers tolerances.

I'm learning how to make flexgears for a harmonic drive out of TPU.  PLA hasn't 
enough flex and breaks in less than 5 minutes running time.

And I've two that have now run at an output speed of about 1 rev in 4 seconds 
for over 24 hours. Unlike the really preciely made metal one's, it has to have 
a touch of backlash, but with a decent driver, and none of the TB series fit 
that description, because they don't auto-throttle the currants, it looks like 
I'll have enough torque from a nema 17 motor to drive the worm of a clone BS-1, 
under cutting load no less.

TPU can be a cast iron bitch, its 100x more finicky about temps and speeds than 
PLA.  Currently seems to be working, but at a nozzle temp 15C above whats noted 
on the no-name box I bought 2 of for a $70 bill.
Virtually zero extruder drive grip allowed in a Micro-Swiss hot end that moves 
the extruder motor to the X carriage.

Thanks TomP, stay safe and well, both of you.

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] precisiomn indexer

[Gene Heskett]

On Friday 28 August 2020 06:18:32 Thomas J Powderly wrote:

> Gene an old client called about using a Newbould indexer on his
> machine.
>
> I remember it was a hirth 'gear' or coupler
>
> Very accurate stacking 'gears' , a way to set a part at precise angles
>
> I thought... "Hey Gene could _print_ one"
>
> as if you dont have enough to do :-)
>
> just FYI
>
> TomP
>
> https://en.wikipedia.org/wiki/Hirth_joint
>
> https://www.youtube.com/watch?v=3EGGuR5YziE
>
The odd tooth version could probably be done in sub-degree jumps but not 
with a 3d printers tolerances.

I'm learning how to make flexgears for a harmonic drive out of TPU.  PLA 
hasn't enough flex and breaks in less than 5 minutes running time.

And I've two that have now run at an output speed of about 1 rev in 4 
seconds for over 24 hours. Unlike the really preciely made metal one's, 
it has to have a touch of backlash, but with a decent driver, and none 
of the TB series fit that description, because they don't auto-throttle 
the currants, it looks like I'll have enough torque from a nema 17 motor 
to drive the worm of a clone BS-1, under cutting load no less. 

TPU can be a cast iron bitch, its 100x more finicky about temps and 
speeds than PLA.  Currently seems to be working, but at a nozzle temp 
15C above whats noted on the no-name box I bought 2 of for a $70 bill.
Virtually zero extruder drive grip allowed in a Micro-Swiss hot end that 
moves the extruder motor to the X carriage.

Thanks TomP, stay safe and well, both of you.

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] precisiomn indexer

[andy pugh]

On Fri, 28 Aug 2020 at 12:47, Peter Blodow  wrote:

> See https://de.wikipedia.org/wiki/Hirth-Verzahnung

Oder auf Englisch: https://en.wikipedia.org/wiki/Hirth_joint

I need an excuse to make one, I have a suitable horizontal milling cutter

-- 
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] precisiomn indexer

[Peter Blodow]

The point is the self-centering action which allows positioning down to 
one arcsec.

See https://de.wikipedia.org/wiki/Hirth-Verzahnung
Peter

Am 28.08.2020 um 12:54 schrieb andy pugh:

On Fri, 28 Aug 2020 at 11:21, Thomas J Powderly  wrote:

Gene an old client called about using a Newbould indexer on his machine.

That's rather clever, using a differential indexer to get finer graduations.

The idea goes back a long time, the same principle was used for
magneto couplings in the early days of motoring:
https://commons.wikimedia.org/wiki/File:Vernier_coupling_(Manual_of_Driving_and_Maintenance).jpg

Though the example in the video seems different, and in fact _appears_
to be using a non-integer number of teeth in the bottom interface...

Another unexpected place that you might find a Hirth coupling is in
the middle of a set of bicycle cranks:
https://www.parktool.com/blog/calvins-corner/campagnolo-ultra-torque-and-record-group





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Re: [Emc-users] precisiomn indexer

[andy pugh]

On Fri, 28 Aug 2020 at 11:21, Thomas J Powderly  wrote:
>
> Gene an old client called about using a Newbould indexer on his machine.

That's rather clever, using a differential indexer to get finer graduations.

The idea goes back a long time, the same principle was used for
magneto couplings in the early days of motoring:
https://commons.wikimedia.org/wiki/File:Vernier_coupling_(Manual_of_Driving_and_Maintenance).jpg

Though the example in the video seems different, and in fact _appears_
to be using a non-integer number of teeth in the bottom interface...

Another unexpected place that you might find a Hirth coupling is in
the middle of a set of bicycle cranks:
https://www.parktool.com/blog/calvins-corner/campagnolo-ultra-torque-and-record-group

-- 
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] precisiomn indexer

[Thomas J Powderly]

Gene an old client called about using a Newbould indexer on his machine.

I remember it was a hirth 'gear' or coupler

Very accurate stacking 'gears' , a way to set a part at precise angles

I thought... "Hey Gene could _print_ one"

as if you dont have enough to do :-)

just FYI

TomP

https://en.wikipedia.org/wiki/Hirth_joint

https://www.youtube.com/watch?v=3EGGuR5YziE




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