Insert grades A A Insert grades Summary of insert grades A2-A5 Turning A2 Small tools A3 Grooving / Cut-Off / Threading A4 Drilling A5 Milling A5 Insert grades A6-A21 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 Insert material selection table A19 Grade properties A20 A1