Hi All,

Question about SFM, I'm cutting 316 SS on a Citizen M20. The stock is .250" dia, all turning. I'm getting recommended SFM from tooling suppliers to people online for anywhere from 300-650 SFM. The largest diameter on the part is .1565" and the smallest .040". using 300 SFM if I'm doing it right that puts me between 7000 and 28000 RPM! My machines don't do that fast and this is definitely incorrect. For Swiss turning particularly is there a formula I should be using to figure this out correctly?