D50442009 - HSS Step Drill For use in sheet metal, aluminium, plastic & fibre glass, ideal for sheet metal without pre-drilling. During drilling, the next step deburrs the previously drilled hole. Fixed Drilling Steps: Spiral Flute for reduced vibration and greater control through steps Made from HSS: Constructed from M2 high speed steel offering the best combination of strength, heat & wear resistance Flat Shank: Three flats suits 3-jaw chuck Shank Flat Steps - 9 Diameter 4, 6, 8, 10, 12, 14, 16, 18, 20mm