View Full Version here: : 2" threads

The Mekon
04-07-2017, 06:07 PM
I have a couple of 2" diagonals one a prism type from University Optics, the other a Bintel mirror diagonal.
My question relates particularly to thread used for the eyepiece holders in this type of diagonal. The Bintel one is 50mm when measured with my verniers, the University prism measures 55.5mm. Are either of these thread standard? Just what is a T2 thread?

My reason for asking is that the University prism is excellent optically but awful mechanically. If I can replace the eyepiece holder with a compression ring type, then I may save the cost of buying and new Baader prism.

Are there any adaptors available for 55.5mm thread?

04-07-2017, 07:34 PM
Hi John,
Baader planetarium do various Clicklock adapters with holders and are great to use as well!
They have a m56 thread that would possibly fit your requirement.
I bought an m72 for my Tak.
Good luck

04-07-2017, 08:50 PM
Ring Steve at Myastroshop hes good at that stuff and has a good stock on hand...

04-07-2017, 09:09 PM
These sound non-standard to me.....
The T thread is a M42 x 0.75 pitch thread.

04-07-2017, 10:20 PM
Old University Optics(UO) gear was machined in Michegan. If so, it may be imperial threads.

Newer UO stuff is made in China. (metric)

Bintel gear is probably Chinese. (metric)

You need to put a thread gauge on it to measure pitch and thread angle. Any decent machine shop could measure the threads and make you an adaptor if you can't buy one.

05-07-2017, 05:06 PM
Hi John,
I have a Bintel 2" diagonal. It is actually a rebadged GSO part and uses a standard SCT thread (2", 24 TPI) for both barrels.
Know nothing about your UO diagonal.

The Mekon
05-07-2017, 06:22 PM
Thanks Darren, Yes maybe the thread is M56, though as Joe says, early UO stuff may be imperial. I checked the Baader site and they do have M56 click lock, but it appears to be a female thread and I need a male thread. Would cost over 80 Euro + post so maybe I will just buy the whole diagonal.

Thanks to all who have posted.