On Sun, 05 Feb 2006 22:27:20 GMT, "mrcheerful
.." wrote:


"Frank Erskine" wrote in message
.. .
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?


Whitworth



Says UNC he

http://www.pixcellent.com/head_seln_01.html

Just a guess but maybe Britain used Whitworth and Japan used UNC?

sponix