GSR HSS High Speed Steel Countersink Drill Bit for MetalHigh Speed Steel Countersink Bit DIN 335 = Countersinks with 3 cutting edges 90 Used for countersinking, deburring and chamfering Conical cutting edge geometry Steel, cast steel alloyed and unalloyed up to 900 N mm tensile strength, grey cast iron, malleable cast iron, spheroidal graphite iron, die casting, sintered iron, nickel silver, graphite, short chip ping aluminium alloys, brass and bronze