[big gear head]

Drill bits come in fraction sizes, letter sizes and number sizes. Then there are the metric sizes too. One of the first things I learned to do in machinist school was to hand sharpen drill bits on a grinder. It's not hard with the larger bits, but small ones are difficult. I've got more drill bits than I can count. 3 sets of fraction, 3 sets of letters and 3 sets of numbers, plus 2 boxes of loose bits.