Thanks for the kind words. I sure don't deserve them, though.

I've only seen S5 on paper/internet. Looks to be tougher and more open to a variety of heat-treatment methods. S7 is used for jackhammer bits, though, so it's a bit tougher than needed and SR77 looks to be tougher still (will need bowie to confirm <img src="/ubbthreads/images/graemlins/laugh.gif" alt="" /> ).