... 2 tight tolerance 3 heat treatment,blacked 4 good delivery machining part1.Material:AISI4140,4142,or4340 Alloy, or other ... machining, drilling and reaming hole, heat treatment and blacken.3.Finish: heat treatment RC 50-55, Blacked, other coating ... reasonable Material,(copperD,aluminium,stainless steel,white steel,iron,alloy availible)Specification,D600*H70 as exactly your needSurface treatment: ( ...