In article ,
Frank Erskine wrote:
I'm trying to find out whether the ¼" bush for a camera tripod is a
Whitworth or a UNC thread - both are 20 tpi, but of course the thread
form is different.
Any ideas please?

It's Whitworth. Dates back to before Unified.

--
*If at first you do succeed, try not to look too astonished.

Dave Plowman London SW
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