It is a 1/2" hole I need.Not sure if I want to experiment with a dremel tool or even a bit for that matter.I have not bought the grips yet but bidding on them.Probably be best to just order from Sack P.In fact,the ones I'm bidding on were made by him/you.I have a very low bid so will be outbid.May be talking to you shortly Sack P on a set.