Good thread. I've got a tip and observation to share, and I also have a question for you guys to ponder on about NS.
TIP:
The trick to drilling NS is to take it easy and use plenty of Cool Tool, Tap Magic, or whatever. Let the bit do the work. Don't try to hog it, or it will overheat and/or bind the bit. By taking it slow and keeping it cool, you'll find you actually get through faster than trying to rush it.
It's easy to tell when you're at the right speed and have the right amount of pressure. Instead of a pulling up chips and chunks, you'll see a nice long spiral of the NS working it's way up out of the hole. It even sounds and feels different when you get it right. I can't explain it -- it just sounds and feels smooth.
I start the hole and back off, then give it a shot of Tap Magic. Then it's back in the hole until that little spiral of NS starts working it's way out and around the bit. Back it out, clean the bit lightly with a small wire brush, add more Tap Magic, and back in again.
OBSERVATION:
With respect to the oxidation, I haven't had a problem with NS turning, though I don't know why. I keep hearing that it will turn like brass. I've got a small hunter with a NS guard and pins stashed away that I made at the bladesmithing school circa 1996. I looked at it this weekend and it hasn't turned.
With respect to the milling of NS, I haven't had any trouble so far. My wife bought me a mini-mill for Christmas last year. The end mills I got from Uncle Al's cut through the stuff like butter at a fairly high speed. Neither the NS or the end mills get hot. I'm a bit perplexed about it, but I "ain't" complaining.
QUESTION:
One thing I agree with hole-heartedly is that the stuff scratches too darned easily. All of us who work with NS know that if it's too hard, you can anneal it by heating it up and quenching in water, which I do all the time. What I'm wondering is if anyone knows how to do the reverse. That is, purposely harden it up a bit to make it more scratch resistant. I don't mean harden in the same sense as a ferrous metal like steel, I just mean make it a little more scratch resistant.