The Secret Life of Components: Screw Threads - video

[Frank S]

I do sometimes use a drill to tap holes. It all depends on the precision that you are after and the speediness it offers. I tend to have better luck with thinner material and also on very hard steel I probably wouldn't use that method.

One sort of thread he didn't discuss is the buttress thread. To be fair it isn't normally used by mechanics and machinists. It was common on caps for toothpaste, ointments, etc., which makes it easier to start the thead to get the cap on easily.

The buttress thread is also commonly used in some band saw vices and quick release vices for drill presses