Camera mount thread

Used to be 1/4 Whitworth, but I think 1/4 UNC is currently provided. See specs of camera in question.

1/4-20 from Home Depot works fine on my brand new Canon or my 80 year old Leica. The Brits were never big players in the camera market so why would it be Whitworth?

The traditional tripod thread is a 1/4 - 20 BSW (Whitworth). The current ISO standard, interestingly, is 1/4 - 20 UNC.

You'd need a near-perfect thread to tell the difference in use.

As for British involvement, it stems from microscopes and telescopes. The smallest optical threads are still BA (British Association).

Optical threads, as you probably know, are a dog's breakfast of mixed inch and metric sizes. The old Leica lens mount, for example, is 39mm x 1/26". Yes, 26 tpi. No kidding. Early Canons were 39mm x 1/24".

Another annoying thing about optical engineering in America is that dimensions for the glass in a lens assembly are in millimeters (because the first optical designers in the US were German immigrants), but the housings are usually designed in inches.

I've used 1/4-20 hardware store bolts on my rigups. Older and larger format stuff used 5/16" Whitworth. There used to be conversion sleeves for smaller to larger. Some of my tripods still have them.

Stan

1/4-20 and 3/8-16 is what I see around. Same deal with the larger thread apparently- used to be Whitworth, now UNC is the standard.

For a mere $40-60 one can access the holy standard of tripod-to-camera interfaces ISO 1222:2010.

Best regards, Spehro Pefhany

It may have been a" Brass thread" as they were all 26 tpi independand of the diameter

Thanks all. That was my guess, but better to ask before screwing up the threads. Karl