Lathe Internal Threading 29 Degree 6ACME Internal Threading Inserts Turning Tool The shank is made of spring steel with heat treatment, shock resistant and durable, not easy to deformation. Shank size is 16mm in diameter. Threaded inserts are made of German carbide, ground by five-axis tool machine, with sharp edges. High-end coating on the surface, high temperature resistant. Can process carbon steel, stainless steel, cast iron and other heat-treated steel Items include SVNR0016N16H 1PCS 16VNR6ACME 10PCS.