Top ring Installation

I think that it's about 1/8", but be careful not to get too large, or you will weaken the bolt where it can break.... :banghead:

It's also a challenge to get it drilled straight and not crooked and into the threads....

I have a few that I can use if I mess one up, but I will use a drill press and go slow and lubricate it well, if not I may be able to find a bolt already with the hole in it.