Insert Grades A A1~A20 Insert Grades Summary of Insert Grades A2~A5 Turning A2~A3 Small Tools A3 Grooving A4 Cut-Off A4 Drilling A5 Milling A5 Insert Grades A6~A20 Cermet A6 PVD Coated Cermet A6 CVD Coated Carbide (Turning) A8 PVD Coated Carbide (Turning) A10 PVD / CVD Coated Carbide (Milling / Drilling) A12 Carbide A14 DLC Coated Carbide A14 Ceramic A15 CBN (Cubic Boron Nitride) A16 PCD (Polycrystalline Diamond) A17 Honeycomb structure CBN / Ceramic A18 Grade Properties A19 Insert Material Selection Table A20 A1