On Wed, 16 Jan 2008 23:50:10 +0000, Christopher Tidy wrote:

That sounds cool. How do you make a tap in the home shop?

I may be doing it the wrong and/or hard way but, I've done it a couple
of times. Once when I had a die of the right size but not a tap - used
it to thread some rod, then just ground out some relief cuts on the rod
to make a tap-shaped object. Very freehand and very much not optimal
angles for anything but, it made the cut I needed for exactly one hole.
Second one was a bit more ambitious, single-pointed a threaded rod on
the lathe and again hand-cut 2 relief cuts. Made the hole I needed.
Probably not the right way but, for this job, was fine. (metric
left-hand thread for one-time use, don't ask).