Size of bolts on SW scopes?

[dlp]

I want to make up a bracket to fit an ST80 to my 200PDS as a guidescope. I just want to make a plate to fit between the rings on the 200 using the pre-drilled holes that are there for a camera mount, and then take the bottom plate off the ST80 bracket to fit the rings to the other plate. However, I need to get some bolts to fit and the threads on the 200 & ST80 don't appear to be metric! Anyone any idea what they are please? I've asked Martin at FLO but his contact is not available until tomorrow - I'd like to toddle off to B&Q or wherever and get this sorted today 'just in case' we get a clear night tonight!

David

Edit: The bolts that hold the rings on to the ST80 bottom bracket are M6, so no problem. It's the 'camera thread' type bolts that fix on to the main scope that are evading me.

[kharga]

They are probably imperial screws! Try to see if you can find a close match in a "proper" ironmongers that sell screws individually!

[jgs001]

The piggy back bolts use camera tripod thread, which is 1/4" whitworth or UNC fittings.

[dlp]

Thanks!

[dlp]

I drilled out the 1/4 Whitworth threads on the scope rings and replaced with M6 - attaching a piece of aluminium 'U' section* between the two to hold the ST80. Seems to have worked a treat, will hopefully try it out presently.

* I elongated the hole at the scope end so I could have some lateral movement (wing nut controlled) should I not find a star in the immediate fov.

David