... HRC60~68, Co9%~12% -High aluminum coating drill bit -For high speed cutting 2 Flute High Speed Tungsten ... the better wear-resistance.6.ZHY-600 series drill bit, grain size 0.4um, Co12%, HRC60, AlTiN coating ... for high speed cutting.7.ZHY-650 series drill bit, grain size 0.2um, Co9%, HRC65~68, ... inserts, collet, chuck, tool holder, tool heads, carbide rod, reamer, nut, spanner, etc. ZHY 2 Flute High ...