... . Solid CBN insert TNMA160408, Machining harden steel with HRC50-67, general gray cast iron with HB about 200, high hardness cast ... .05-0.12 mm/rev; Cutting deepth, about 0.2mm General gray cast iron with HB about 200, Cutting speed, 500 ... -0.3 mm/rev, Cutting deepth, about 2.5mm CBN inserts for cutting tool