Multi diameter HSS step drill, provides the ability to increase the sizing of drilled or punched alignment holes accurately without changing tools. A rapid drilling tool ideal for mechanics, panelbeaters or fabricators. Drill diameters from 4 - 30mm in 2mm increments, without the need to change tools.Spiral flute provides two cutting edges for faster drilling and includes edge breaker & self starter. Step drill has a deburring zone which can deburr the cutting edge. 10mm shank.