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Hi Kim, 304 is an austenitic Cr Ni stainless steel (18/8), and I find it more difficult to turn or mill than the freecutting 303 grade. If you are going to turn the stainless steel my advice would be 303.Thor
I also agree that 303 is much more machinable than 304. I'll add that I like 416 -another free-machining grade- even better than 303. The 416 is generally only available as round stock. I see onlinemetals has it.At speedymetals.com I like to look at the characteristics of the various metals, which include "machinability". For steels, they give machinability as a percentage of a reference steel B1112 (which I know little about). In other words, in this comparison B1112 would have a machinability of 100%. For comparison, here are the machinabilities of the three stainless grades discussed here:304 SS: 45%303 SS: 78%416 SS: 110%And for one more comparison, 12L14 leaded steel has a rating of 193%.--Tim