Help: Toyo 810G mounting block tripod thread bigger than 3/8"

[MatchingMole]

I've just bring back home a nice and heavy toyo 810G camera, and at the moment to put it on my tripod head it appears the tripod thread on the block is bigger than 3/8 size (see photo, around 12mm diameter), so no way to mount the camera on the tripod

I have found on internet that it seems to be a thread adapter. Do you knowwhich size is it?

See two photos:
- my mounting block with the too big thread (around 12mm diameter)
- photo found on internet of the same model with thread adapter

Thank you in advance for your help!

[pendennis]

Looks to be 12.5mm +/- in diameter. I'd say you'd need a 1/2" to 3/8# bushing. It may be that the camera originally had one, but the previous owner removed it.

[gypsydog]

My 810M came new with adapters for both 1/4 and 3/8 that screw into the base, your 810 monorail should be the same. Contact Toyo or try B&H for replacements.

[MatchingMole]

thanks guy for your reply, I have sent an e-mail pics the pictures to the toyo technical support...

[Neal Chaves]

That is not a Toyo rail clamp pictured for Toyo 810 G or GII. The OEM factory clamp for the Toyo 8X10 monorails is only slightly more robust than the 4X5 G rail clamp. Definitely l
not suitable for the long lenses many want to use on the 810G. I made one up from two 4X5 clamps on a plate that bolts to the top of my Majestic head.

[Drew Wiley]

There's a possibility it matches the 5/8-11 thread standard of most survey tripods, even internationally. So you could try a 5/8-11 to 3/8-16 adapter. But thread adapters are so cheap that you could order more than one size if needed.

[MatchingMole]

Thank you for your replies and advices.
I have found on ebay japan for very cheap the rail clamp for 45 model. It’s on the plane now…
Even if it’s a bit narrower that the original 8x10 clamp, I don’t have long and heavy lenses.