I need a 3D printed ER 25 5/8 collet

[Cadillac STS]

I am working on a project for my telescope. I planned to use an ER 25 collet holder and a 5/8 collet for a brake on a 5/8 shaft. Turns out with a metal 5/8 collet there is no slip at all it just grabs like it is supposed to used as a collet holder.

If I could get an ER 25 5/8 collet 3D printed with the most slippery plastic it may work for me.

I checked and there are files online to run to print that part. I would need 3 of them to be able to experiment with fit if needed.

I am working on an all metal “Zlomotion” system ( can YouTube that if interested) to put fine tuning motion into a dobsonian telescope. The azimuth it too loose so I am remaking the bracket to include the brake.

If interested please contact me with cost and time frame to make them.

 

[whitmore]

Could you machine up a collet from something slippery, like Zamac? Polymers and friction
and a high-force clamp... that inspires me to uncertainty...

 

[extropic]

Alternative design suggestion:
Make a collet out of Delrin or nylon.
The external and internal dimensions to be standard.
But, slot only the top (short) end of the taper. Maybe 8 slots equally spaced (45°) down through the annular groove.
That way only the top will bend in and not cylindrically crush like a real collet.

If you don't get enough grip from slotting the short end, make another but slot only the long end of the collet.

 

[Cadillac STS]

Alternative design suggestion:
Make a collet out of Delrin or nylon.
The external and internal dimensions to be standard.
But, slot only the top (short) end of the taper. Maybe 8 slots equally spaced (45°) down through the annular groove.
That way only the top will bend in and not cylindrically crush like a real collet.

If you don't get enough grip from slotting the short end, make another but slot only the long end of the collet.

Good ideas but I thought having one 3D printed would work best.

‘The ER 25 holder is at its limit with 5/8 or I would put in a Teflon sleeve. I could have if I went with ER32.

 

[Cadillac STS]

The purpose is slow motion of the shaft by hand. Not heavy work or any high speed use.

 

[extropic]

Good ideas but I thought having one 3D printed would work best.

‘The ER 25 holder is at its limit with 5/8 or I would put in a Teflon sleeve. I could have if I went with ER32.

You'll know when you try it.
Good luck

 

[Cadillac STS]

I decided to change the design and went with an ER32 Collet chuck. I already had a set of collets for my wood lathe setup.

I used the 13/16 collet and machined a piece of Teflon rod that would be 13/16 outside and 5/8 inside with a shoulder on top. That way the collet will close on the Teflon rod bushing and it is thin enough to adjust tension on the 5/8 stainless steel rod. Worked great,

Someone did offer to make me a 3D printed ER25 5/8 collet and I would still like to get that to try since I have the part and need to make another one.

This is a very old Dobsonian telescope I got on Craigslist to use as a test mule for a project for my main larger one. It gives it micro adjustment while also allowing full free movement.