Just use a ceramic tip tool. The traingular 3 tips type in a holder. The tips already have the slight radius required as design and you get total sharpness and virtual negative rakes as recomended by Dupont for machining all their plastics. A small top tip fixed asa chip breaker and away you go.
I find 700 rpm works perfect on typical 25mm dia regardless of the correct speed calcs for the diameter.
Same tool and a 1000 rpm with the stainless on moderate feed rates.
I polish the finished stainless with 1000 grade for mirror finish.