What size screw do you find on a camera tripod mount

[beamer3.6m]

I have kindly received some guidescope rings and am wondering if I will be able to attach them directly to the scope rings on my 8 inch newtonian by the screw which usually allows a camera to be piggybacked on the rings.

The guidescope rings have M6 holes in the bottom so ideally the camera tripod fitting screw is M6 also but I undertand the tripod could 1/4", but is this the same as M6?

Cheers

[steppenwolf]

The screw is a 1/4" Whitworth and sadly, not compatible with M6. You could mount a bar to the top of the existing tube rings using 1/4" Whitworths and then attach the new tube rings to the bar (from underneath) with M6 bolts like this:-

[George]

Think you can get away with UNC too tho the pitch is slightly different.

[beamer3.6m]

I thought that might be the case. Bummer.

I just need a dovetail bar which should not be too difficult to come by.

[saturn5]

Think you can get away with UNC too tho the pitch is slightly different.

Pitch is the same,they are both 20 threads/inch.

The difference is in the thread angle.

Whitworth =55 deg

UNC =60 deg.

[beamer3.6m]

I solved this by tapping the scope rings with an M6 tap.

It worked, I am a little shocked to say the least as my DIY skills are not up to much and I have never 'tapped' anything before.

I can now use M6 screws directly attached to the scope rings which makes much more sense than the 1/4". I could not even find these in the shops yesterday, everything had an 'M' number.