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ST fibre optic connector -thread size??


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To do some trials with fibre optic connections to the telescope and spectroscope I've bought a couple of the adaptors # 200-350 as shown in the attached link.

Does anyone in the industry know what the thread on the connector is??? About 9mm diameter - BSW/ metric or what???

Tried google but just gives various designs and various threads ie M8 x0.75, 5/8" x 24 UNEF not the one I seem to have.

(I'd like to machine an adaptor to fit the 1.25" focuser with the connector threaded in the center.)

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Used to have this info a few years (and companies) ago as we used to make fibre coupled laser handpieces ... I can't find it now and its driving me potty!!!

If its the end which fixes the adaptor through a bulkhead it could be anything as its only the fibre connector end that were standard... Is it FC if it is its covered in the FOCIS 4 TIA-604-4-B Standard ...Tried all my usual suppliers for data sheets and I have come up a blank.. unless you want to pay for it :hello2:

Try and get the info of the supplier is the only hope...

Forgot to say... as a stop gap in the past we would often just machine the thread back and make it a press fit into the adaptor and used epoxy to secure the parts together...... A bodge I know but still maintained the critical alignment...


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I have just checked the ST adapters I got for my artificial star project (same as yours from the same supplier).

I drilled a 1/4" hole and then tapped it out using a 3/8" NF24 tap. The ST adapter seems to thread perfectly onto the hole.

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