Originally Posted by Steve Smith
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.
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