3/16"-1 3/8” M35 Cobalt Step Drill Bit, Three Spiral Flutes Hex Shank Unibit Drill Bits for Metal, Stainless Steel, Aluminum, Wood, Plastic. 19 Sizes

• TiALN COATING: TiALN coating has excellent characteristics such as high hardness, high oxidation temperature, strong adhesion, small friction coefficient and low thermal conductivity. TiALN coated cutting tools can be used for hard materials and high speed cutting.
• THREE FLUTES STEP DRILL BIT: Ordinary step drill bits are prone to deflection during cutting, but three flutes step drill bits are more stable. The service life of three flutes step drill bit is twice as long as that of ordinary step drill bits; the drilling accuracy is significantly improved; and the cutting efficiency is much higher than ordinary ones.
• M35 COBALT: M35 cobalt HSS step drill bits are more suitable for hard working materials, particularly adapt to drill stainless steel, cast iron, high temperature alloy, titanium alloy and even hard plastics and woods. And a must-have for handyman or professionals, perfect for home repairs and light jobs.
• HEX SHANK: 1/4" hex shank is easy to be installed on impact driver, quick change. And eliminates shank spinning in drill chuck. The step drill bits set for metal are suitable for home DIY, general building and engineering uses.
• STEP DRILL BITS SIZE: 19 sizes (3/16", 9/32", 3/8", 7/16", 17/32", 5/8", 11/16", 25/32", 7/8", 29/32". 31/32", 1", 1-1/16", 1-1/8", 1-5/32", 1-7/32", 1-9/32", 1-5/16", 1-3/8")