I'm no machinist but I do know that steel will turn blue if using a cuttoff wheel and it sits in one place too long and overheats the metal. Maybe not with stainless.

I wondered why the frisbee was getting bigger......and then it hit me. '05 BA - Mulberry/Graphite,128 mains,42 pilots,TBS needles,drilled slides,debaffled stock pipes,Uni,no snorkel