tap and die set?
we have a place called varco industrial not sure where you can ge tthem from in the U.S. but
I love the spiral point taps that i can get from them. Work awesome for power tapping
the interrupted tap works like butter in stainless
http://www.newmantools.com/taps/styles.htm
for general ideas about tapping The taps listed above cost a bit more cash I think i use the brand DORMER alot, but i may have the wrong name