Special step drill for screw holes, the HSS step drill for burr-free drilling of through holes for screw hole pull screws M8(3/8')-M10(7/16')-M12-M16-3/4'-M20 in material up to 4 mm thick. Suitable for use in hand and pillar drills, a total of 9 drilling steps, mounting shaft (10 mm Ø) with 3 driving surfaces prevents slipping in the drill chuck. PU: 1