Ball Mill Dittel 3d Die

15-05-2013 i'm having a heck of a time achieving a good surface finish on some 3d surfaced tools steels.I'm machining 4140 pht, a-2 and d-2.The a-2 and d-2 are soft.I'm finishing with 1/4" and 3/16" 4 flute ball mills.Only 2 flutes are to center.1/4" is running at 8000 rpm and 60 ipm with a.003" step.