I read this message from Bob and it got me thinking. I didn't even recognize the difference in twist drill split point angle (note the beginner's forum!) but when checking my drill bits, I find them to be 135 degree tips. Sigh, and I just ordered a set of 60 degree center drills. Looking at 140 degree spot drills- they seem to be quite a bit more expensive. Can I use these 60 degree center drills with my 135 degree drill bits? I mean- better than nothing, right? Why does it seem that 135 degree twist drills are far more common than 118 degree? Besides accounting for the drill bit tip angle, when does one use a spotting drill vs a center drill? What is the intended purpose of those two things? I had never heard of a spotting drill before. Does there exist a 140 degree (or maybe it's 70 degree?) center drill? Is it worth investing in a couple $30 spotting drills, or buying a whole new set of 118 degree twist bits? Seems like some good advice below, Bob. Just looking to fill in some holes in my understanding.