Solid carbide step drill,hss & carbide step drills,hss coated step drill 1 OEM &ODM Service 2 ISO9001 3 ... 100% virgin tungst Solid carbide step drill,hss & carbide step drills,hss coated step drill GradeCompositionGrain Size(um)Density(g/cm3 ... -resistant alloy steel, cutting of small and medium sized cross section of high speed finishing ,are processed reamer, aluminum alloy ,red ...