HSS CO M35 Triangle Shank 4-12/4-20/4-32MM Spiral, Straight Groove Broca Metal Step Cone Drill Bit Stainless Steel Hole Saw Cutter Parameters: 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. The M35 step drill bit can be utilized to drill holes in the stainless steel plane. Product Material: HSS Co White steel Style: Spiral, Straight Groove Shank: (approx.) 1) 4-32: 10 mm/0.39 in (triangular cylinder shank ) 2) 4-20: 8 mm/0.31 in (triangular cylinder shank) 3) 4-12: 6 mm/0.24 in (triangular cylinder shank) Size: (approx.) 4-12 mm (4mm, 6mm, 8mm, 10mm, 12mm/0.16in, 0.24in, 0.31in, 0.39in, 0.47in ) 5 Steps 4-20 mm (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm/0.16in, 0.24in, 0.31in, 0.39in, 0.47in, 0.55in, 0.63in, 0.71in, 0.79in) 9 Steps 4-32 mm (4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm/0.16in, 0.24in, 0.31in, 0.39in, 0.47in, 0.55in, 0.63in, 0.71in, 0.79in, 0.87in, 0.94in, 1.02in,1.10in,1.18in,1.26in ) 15 Steps The following points that you need pay attention to: 1. 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 boards whose thickness is about 2-3 mm/0.08-0.12 in; 2. The drilling sped can't be too fast on the stainless steel plate. Hundreds rpm is enough. 3. Please add the water or cutting fluid to cool down during the processing so as to extend the service life of the drill bits.