1. Long working life, high efficiency. 2. Uniform surface finish. 3. Reduces machine down time. Solid CBN insert TNMA160408, Machining harden steel with HRC50-67 ... /rev; Cutting deepth, about 0.2mm General gray cast iron with HB about 200, Cutting speed, 500-1000 m/min; Feed ... .5; Cutting deepth, about 3.0mm High hardness cast iron with HRC50-64, Cutting speed, 50-100 m/min; Feed, 0 ...