What size screws in TS extension tubes?

[swag72]

I am looking at making a couple more holes in my TS extenstion tube so that I have 3 screws holding everything secure instead of just one.

Does anyone know what size screws they are? There seems to be some universality about them as they are the same size thread as in my Baader 2" adaptor as well.

Looking to get a couple more, and while I could use a bolt I suppose, I want the proper 'thumb turny' screws.

[Damo636]

Probably M4 but hopefully someone will confirm.

[swag72]

Where can you get these screws from?

[Merlin66]

http://stargazerslounge.com/diy-astronomer/89408-socket-head-screws-bolts.html

http://www.rosshandling.co.uk/t-screws-t-grips.asp

http://www.metric-thumb-screws.co.uk/?gclid=CK6_ipzai64CFUYLtAodE1dW5g (Not cheap!!)

M4 sounds about right.

If you drill and tap a couple of more holes, make them slightly offset to the axial position of the existing - this gives a better clamping effect.

[swag72]

Cheers Ken. I've not got a tapping thng, so planning on going into my local metal guys and just getting them to quickly tap a couple of holes.