Rather than tapping blocks for Nylon or steel wing bolts there are brass threaded inserts that self-screw into a plain 5/16" hole that are pre-threaded. 



http://www3.towerhobbies.com/cgi-bin...LXK034&P=7

Or just a "T" nut under the block works as well. 

You don't need to buy a 1/4-20 tap, pilot drill and wrench.