Quote Originally Posted by ductape View Post
That deal with making left hand thread using a right hand tap should not work because the cutters are angled in the wrong direction. Grinding it thinner causes more problems. It is clearly doable with the 6mm example, but couldn't possibly make very good threads. Larger sizes would be even worse. Getting the correct thread tap seems like a better option.

Spot welding aluminum using the stainless bars feels like an old welder's trick but was new to me. That was pretty interesting.
It would not make very good threads but depending on the situation it might do. A left hand tap would be ideal but you probably don't have one in your shop. The four jaw chuck trick will work with a self centering chuck but most people if they have one at all it will usually be one with independent jaws. You could use it but it wouldn't be as quick.