Quote Originally Posted by Steve Smith View Post
tripod threads were traditionally 1/4" and 3/8" British Standard Whitworth so you might find both Whitworth and UNC.
While that's true, it makes no difference in the case of photographic tripods and camera mounts.

The 60° UNC and 55° Whitworth threads are inter-matable except when component tolerances are very tight,
which is not the case with any photographic equipment.

- Leigh