Quote Originally Posted by susieq View Post
There are left-handed drill bits? Never knew that!
Yes, it's not an apprentice joke this one.

"Left-handed" (alternatively "left-hand") needs some qualification: hold a regular drill bit in front of you with the tip pointing upwards; the flutes curve upwards to the right. On a left-hand drill bit the flutes curve upwards to the left. I'm not sure what all the uses are of a left-hand drill bit, but one very handy one is to enable you to drill into an embedded bolt or screw whose head has snapped off and extract it using the rotational force of the bit. It doesn't always rotate the bolt out, but often does. If it doesn't there are other means you can resort to.