We may receive a commission on purchases made from links. You can tell a dull drill bit more or less immediately. If you're drilling wood, you'll likely see thin wisps of smoke as it starts to burn.

Getting into machining is hard. From high-speed seel versus carbide to “old US iron” versus “new Asian manufacture” to simply choosing which drill bits to buy, many hard decisions must be made before ...

I've been thinking about buying one of these but I don't know if they are just a gimmick. Also, if they genuinely work well how good do your bits need to be in the first place to be worth sharpening?