Tripod thread foms, BSW or UNC or ?
I was investigating this issue myself via Google and came across your post.
Apparently tripod mounts used to be BSW, but has at some point (1972 it appears) changed to UNC. The latest ISO standard on the matter seems to be ISO 1222:2010
A fairly simple question but seemingly not one with a readily found answer.
I have seen that the common thread in the camera base is 1/4" 20TPI but those specs from memory fit BSW or UNC, british standard whitworth and unified national course.
Ditto the larger head mounting thread, I think I have seen it is 3/8" 16TPI which again mayches BSW or UNC
BSW and UNC are from memory not interchangable as BSW has a 55deg angle which UNC has a 60deg angle.
Thanks, sorry if I missed it in my trawl of "tripod thread" threads.