Ultra large tripod threads?

petrochemist · Jan 8, 2020

I tried to use my second large format camera tonight, and met an unexpected hitch, the tripod mounting screw is for a bigger thread than 3/8-16. It looks to be about 1/2" diameter does anyone know what thread this would be?

480sparky · Jan 8, 2020

Try a ½" bolt in it.

Derrel · Jan 8, 2020

12mm?

petrochemist · Jan 9, 2020

480sparky said:
Try a ½" bolt in it.

Sounds simple but I'm in the UK so our 1/2" bolts wouldn't fit anyway. 1/2" bolts are generally antiques here & usually would be BA rather than Whitworth let alone UNC (Whitworth is at least close to UNC the 1/4" varieties do work)

Derrel said:
12mm?

A possibility that I can easily check using Sparky's technique, but I think it's quite a bit bigger than that.

Further googling eventually found mention of a 5/8-11 thread used for surveying tripods, it's probably that.
Typically most of the reducers to 3/8-16 from 5/8 are for the much finer pitched microphone thread. I did find one for power tools going from 5/8-11 to 3/8-16 but the seller doesn't ship to the UK & only sells large packs. so I can't even get one & cut the hex head off.

There are 5/8-11 to 1/4-20 reducers around but I'm not sure a 1/4" thread is man enough, so I'm probably best off just getting a different tripod connection for the monorail.

zombiesniper · Jan 9, 2020

Amazon thread adapters.
Another one

petrochemist · Jan 9, 2020

zombiesniper said:
Amazon thread adapters.
Another one

Both of those are for the much finer pitched microphone thread, 27 tpi rather than 11 tpi.

tirediron · Jan 9, 2020

If it's North American, it should be 1/2NC (1/2-13), however if it's British (or European in general), it may be BSW; 1/2-12.7, in which case you'll likely need to make your own adaptor.

zombiesniper · Jan 9, 2020

Didn't notice that.

Here's the only thing I can find in that pitch.

Original katomi · Jan 9, 2020

petrochemist said:
I tried to use my second large format camera tonight, and met an unexpected hitch, the tripod mounting screw is for a bigger thread than 3/8-16. It looks to be about 1/2" diameter does anyone know what thread this would be?

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