Description Doersupp 4 22mm Hex Shank Step Cone Drill Bit HSS Titanium Coated Hole CutterSpecification MaterialHigh speed steel 4241Size4 22 mm 10 Setps 6 8 10 12 14 16 18 20 22mm Shank6mm dia 25mm L Total75mm L Features The ladder of its unique structure a bit can open a variety of specifications of aperture Do not need to use center punch compared with the ordinary twist drill is not easy to be broken Deburring chamfering elliptic hole enlargement twist drill the function of themwas unable but it is possible The use of tools drill bench drill Work while water cooling can effectively extend the service life of drill bit recommend drilling rate of 250 250 RPM Package Included 1 x Step DrillMore Details