I had several collets made from the Tom Jobe, etal prints that
are in the file section of this group, and they were made from
a single piece of brass rod... threaded section and all. They
worked perfectly.

The group that developed that print, machined several out of
aluminum and they worked fine too.

They used an ordinary thread cutting die to cut the threads on
the threaded section. I suspect that they flipped the die for
the last pass to make the threads cut up to the edge... but there
is no need for them to be cut all that close to the collet body.

-Chuck Harris

Tom Gardner wrote:

I made my own model from the dimensioned prints, and had some made from SLA. I used a
file to make it fit, and have experimented to see how the SLA took the forcibly
inserted screw thread. The results were sufficiently encouraging that I've sent a
modified variant off for manufacture.

A standard home PLA printer definitely won't work. I tried it to assess the relative
quality of a nearby 3D printer, and the results were what I expected: dimensionally
inadequate, and it easily fractures along the joints between layers.

I don't know about the SLA's long-term stability. I do have SLA with a 2mm pitch
thread from 3 years ago that is fine

I don't know about the SLA's long-term stability under heat. I hope it won't get too
hot.

The parts could be manufactured in brass or aluminium, but I don't know whether the
screw thread would be of adequate quality. If not then manual tapping would be
required. They would be more than an order of magnitude more expensive, but still
tolerable. Hence I prefer experimenting with SLA.



On 10/11/19 00:41, Tony Fleming wrote:

Where are the 3D files to print my own replacement?
Thank you very much.
Tony


On Sat, Nov 9, 2019 at 6:39 PM Chuck Harris <cfharris@...> wrote:

More usually, the problem is someone turning the
slotted screw, thinking it loosens the collet.

Turning the screw will break the collet every time.
Tightening the nut is less likely to do that, as that
is the intended way to apply force to the collet.

It is the torque that causes problems.

There are dimensioned prints for the collet in the files
section of this group. A search on collet should find them.

If you can't find them, contact me, and I will send them
to you.

-Chuck Harris

DaveH52 wrote:

Are there any of the fan to motor collet thingies available anywhere?
When I removed the back panel, the fan fell out. I think someone

tightened it up too much and broke it on the scope I'm rejuvinating.