M35 Four Spiral Flute Cobalt Step Drill Bit Set 1/8"-7/8", Industrial, 3Pcs FOUR-FLUTE STEP DRILL BIT: Four-flute step drill bit is designed to provide greater stability, the cutting blade design improved accuracy and cutting speed guaranteeing a faster and smoother cutting. TiAlN COATING: Featuring an industrial-grade TiAlN coating, extremely hard, can withstand high oxidation temperatures, and has excellent thermal hardness, which can minimize the wear of the drill bit during each drilling process. M35 COBALT HSS STEP DRILL: M35 cobalt HSS has the characteristics of high red hardness, high wear resistance, and sintering resistance. It can be used on materials like wood, plastic, aluminum sheet, copper, other metal sheets, and stainless steel. SUIT YOUR NEEDS: 34 total step sizes include 3 bits with 1/8" - 1/2", 1/4" - 3/4", 3/16" - 7/8".135 cutting angle reduces self-wear and provides a larger stress area, resulting in cleaner, more efficient drilling for home repairs, and metalworking. QUALITY COMMITMENT: Add cutting oil or spray water to cool during continuous use, any quality problems, please feel free to contact us.