Optical tube adapters

In fact just a ring with internal thread and external thread.

I was going to recommend MXV photographic who had most things by way of obscure adapters and if they didn't could make bespoke ones for a price. Telescope House is also worth a punt some of the expertise went there.

Otherwise try Edmund scientific optics online catalogue or Surplus Shack and cross your fingers that you get lucky. Otherwise find a tame local mechanical engineer with a lathe that can do thread cutting.

Yes, thanks for the suggestions Martin....if I had a lathe I could do it myself.

Have a look on thingiverse.com first to see if anyone already designed the right thing. There's lots of adapters already on there.

Theo

Yes. My thoughts exactly. The OP may not be aware he can e-mail the design to various suppliers and they will post the printed article back to him.

Another Dave

If you mean the 2nd hand camera shop in Uckfield, they vanished in 2009.

Thanks for the info. You reminded me of another TLA business that might also help: SRB

One thing I would warn about this style of adapter, is if they're constructed of metal, they leave some play in the threads, so the item will not jam up when screwed together.

There is sufficient play, that you cannot get a good focus from the optics. Maybe you get it set up, it merely touch the steel part with light pressure, and your focus is thrown off.

I would suggests some other material choice, such that when the threads engage, they're more of an interference fit.

I discovered this, from some parts I bought years ago, and never could get the setup rigid enough for it to keep the focus I'd applied. A little tap here or there, some incidental contact and the focus would be off.

Paul

A spec of locktite on the threads before you do final assembly prevents there being any tolerance slack. I haven't found that play in the threads to be much of a problem in any of the optical systems I use.

The old Zenit and Pentax cameras used M42 threaded lenses for instance.

Normally two surfaces get squeezed together by the thread and hold fast.