Hi,
Can anyone tell me what size the screw thread is, where the pan bar/arm screws onto the tripod head? I want to try attaching another accessory onto the head using this screw thread but I'm having difficulty finding the correct screw size

It's a 1/4 x 20 bolt. I'm doing the same thing by mounting my 5" LCD monitor to it.

Thanks James

Unless the 503 head is different from my 501, the bolt that holds the pan bar onto the head (thru the toothed rosetta clamp) is a 8mm x 1.25mm pitch bolt. I just recently went thru this when building a "sled" to mount my microtrack recorder to the un-used side of the head. The only 1/4-20 thread I've found on the 501 head is the one that screws into the camera to hold it to the quick-connect dovetailed slide.

As I mentioned though, mine is a 501; looking at B&H site, that part looks the same... Steve

Hi,
Can anyone tell me what size the screw thread is, where the pan bar/arm screws onto the tripod head? I want to try attaching another accessory onto the head using this screw thread but I'm having difficulty finding the correct screw size

...if that info was included in the meager documentation that comes with the head? I've also considered using the screw hole identified as an "M10" size to attach things at the top of the single leg-frame, but I'm not sure what "M10" means. At least the documentation mentions that the hole is for a carry strap.

Personally, I can't understand why Bogen/Manfrotto finds it so hard to include that in the printed material.

If you find the correct size, please report back. I'd certainly be interested in knowing what it is.

M10 means metric 10mm-there are 2 pitch sizes to metric threads. get both at the hardware store to validate which thread pitch. I would assume it's the coarse thread.

M10 means metric 10mm-there are 2 pitch sizes to metric threads. get both at the hardware store to validate which thread pitch. I would assume it's the coarse thread.

That's a big help. Now I hope to be able to fashion some sort of connection for peripherals. I think I'd rather attach a small monitor with that screw instead of a typical shoe mount.

If others have done the same, I'd appreciate photos of how it was done.