I use them a lot at work, on anything less that 0.100". The key to using them, and not destroying the edge, is to slow down the drill as you get to bigger and bigger steps. I have seen many people destroy a uni-bit by trying to drill a 3/4" hole on high speed. Usually all that happens is you will work harden to metal, and dull your bit.
Another consideration is to see which edges are sharp. You can buy some bits that have two cutting edges, so once one edge dulls you can reverse the drill and you have a brand new bit. The reason you can do this is because a uni-bit does not have spiral flutes, just a strait channel.
Last edited by Redlegs48; 01/13/2013 5:21 PM.
