It is suitable for use on wood, plastics and non-ferrous metals and has a cylindrical shank system. The HSS Countersink Bit, Cylindrical Shank performs smooth countersinking for screws and deburring of holes in soft materials. The ground countersink is made of HSS (high-speed steel) that offers an optimum surface quality for even work in pliable surfaces. Excellent results in soft materials are made possible by five 90-degree cutting edges that continuously work free of chattering and without leaving burrs.