Step Drill for Cable Glands Combined HSS step drill for making core and through holes for cable glands With spiral groove and deburring zone No centre-punching necessary, drill bits do not run Better flowing and paring cut through spiral groove Constant cutting angle during the whole process Suitable for construction steel, CrNi steel and non-ferrous metals up to 6 mm thick Diameter specification is lasered on every level Three-faced driving shaft, prevents slipping in the drill chuck 标准   DIN 335C 高速钢刀具和套件