303 vs. 304 stainless steel

[pearldiver]

How different is the "machinability" between 303 and 304 stainless?

[Geof]

Very different.

303 does not work harden to the same extent, the chips have a tendency to break of instead of forming long strings and tool life is two or three times better even when running at a faster speed.

It is not as corrosion resistant as 304 and it is not suitable for welding.