HSS M35 5%Co Hex handle Step Drill bit. 4-12mmX5 Step (4, 6, 8,10,12mm)? 4-12mmX9 Step (4, 5, 6, 7, 8, 9, 10,11,12mm)? 4-20mm (4, 6, 8, 10, 12, 14, 16, 18, 20mm)? 4-22mm (4, 6, 8, 10, 12, 14, 16, 18, 20, 22mm)? 5-21mm (5, 7, 9, 11, 13, 15, 17, 19, 21mm)? 5-27mm (5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27mm)? 4-32 mm (4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32mm)? Main Functions Of Product:? M35 cobalt step drill (HSS Co) is a high hardness step drill bit that is mainly applied for drilling high hardness steel, such as, the stainless steel plane and hardened steel. M35 step drill bit can be utilized to drill holes in the stainless steel plane. The following points that you need to pay attention to:? You can use the hand drill and bench drill to drill holes in the stainless steel plane. Use the hand drill for the board whose thickness is within 1 mm/0.04 in, while use the bench drill for the board whose thickness is about 2-3 mm/0.08-0.12 in;? The drilling speed can’t be too fast on the stainless steel plate. Hundred rpm is enough. Please add the water or cutting fluid to cool down during the processing so as to extend the service life of the drill bits.