Originally Posted By: 92saturnsl2
The usual HSS (high speed steel) bits have always worked great for me. You have to match drill speed for the diameter of the bit. Small bit = higher RPM, large bit = slower. I don't usually use oil unless I'm using a dull bit, or drilling into something hardened, like a high grade bolt or something. Don't buy your bits at Walmart or Target.. Lowes/Home Depot can be hit or miss. Quality bits are usually found at your local construction store-- Whitecap, HD Supply, even Fastenal sells good ones. If it's cheap and has a fancy gold or other colored coating, you're buying garbage, in my experience. I've seen two good kids: regular HSS, and the titanium and/or cobalt ones that cost a pretty penny. Both are good, the latter is better.
I agree. All too often people say to "Go slow" when drilling. Not always true. As you said, drill speed or lathe RPM (really tool surface speed) is a function of bit diameter or material diameter in a lathe and also material.
Also see lots of chatter about pilot holes. Well depending on the bit size and design, you may not need one. We had two Lawson reps come through the other day (two really good looking ladies who knew their stuff) and let us demo their Regency series bit. She specifically stated NOT to use pilot holes up to the 1/2" bit in their index as is would lead to chipping of the cutting edge. She also said she could tell who was using a pilot hole when it came time to warranty a bit. Due to the design of the point, you just drill and go. We were able to run a (approximately) 3/16" bit through the shoulder of one of their grade 9 bolts. No center punch, no pilot- just put the drill on and go.
It made us believers- we ordered one of their indexes, which was really competitively priced!
