Thread size for tripods?

[Evangelion]

I hope I'm not asking a really stupid question here (be gentle with me, I hardly ever read this section) - but some friends and I were talking recently about attaching cameras/camcorders to rollcages, and we realised that none of us actually knew what type or size of thread is used for the screw attachment on the bottom of a camera!
I assume they must all be the same, otherwise they wouldn't fit the tripods. Can anyone enlighten us?

[Magic919]

1/4 nice thread is standard. Whitworth I believe.

[S47]

Definitely 1/4" whitworth on all small cameras, and light lenses.
If you happen to use a large and Heavy lens then It'll also have a second larger thread this is 3/8" Whitworth.
Some clever [Expensive] tripods/Monopods have these 2 threads on one fitting, the 3/8" sliding into the Monopod automatically when you attach a 1/4" threaded Camera