Dave Osborne wrote:

There was a discussion on here maybe earlier this year, maybe last year
about whether the thread on a tripod/camera was 1/4-20 Whitworth or UNC.
ISTR we got into discussions about thread angles and somebody pointed
out that Wikipedia was (allegedly) wrong.

Thing is, I can't remember who had the last word, and I can't find the
discussion on Google Groups.

It's Whitworth. I've just fished out one of my ancient cameras that dates
back to the early '50s when the standard was Whitworth. It's held in it's
ever-ready case with a screw which goes into the tripod bush and has a
female thread on the bottom for mounting on a tripod while in the case. The
screw fits my current digital camera and also mates with the screw on my
fairly recent tripod. So I'd say that the current standard is still
Whitworth, or is given a generous clearance so that both Whitworth and UNC
will fit.

--
Mike Clarke