When assembling my Hadley, I didn't have any screws with thumbheads so I decided to make a thumbhead that attached to the extra #10-24 screws I did have. 

I made this thumbhead very slender and long in order to hide behind Hadley's spider. They work great on 1.5-2" screws for the secondary collimation screws and 0.75" screws for the focuser.

To use, slide in a machine screw and tighten the head on with a nut from the bottom as seen in the pictures.