HSS Center Drill centre drill A type B type 1.Material: Hard alloy,HSS6542,9341,4341,4241 2 ... .Surface treatment: bright finish HSS Center Drill centre drill A type B type1.Material: Hard alloy,HSS6542,9341,4341,4241 ... 2.Surface treatment: bright finish 3.Size: A type 0.5-6.0 B type 1.0-6.34.Technicial:fully groundCenter ... factory for further cooperation. HSS Center Drill centre drill A type B type