The self-centering tip and the precise cutting edge of the conical drill cut the material in a targeted manner without getting lost. Straight flutes provide optimal chip ejection.HSS high speed steel lasts longer than others. The titanium coating ensures that sheet steel, aluminum sheets, copper, plastic and wood sheets and many other types of sheet metal can be easily cut.Perfect for home repairs and light work like drilling holes in plastic, aluminum, copper and many other types of sheet metal. Not for stainless steel.Package includes: 1 x 6-60mm twist flute HSS step drill bit (12 steps: 6mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm , 60mm) Features: 6-60mm pitch drill bit suitable for workpieces with hardness less than 25, such as carbon steel, sheet metal, insulation board, PVC board, plank and wood. The thickness of the plate under 5mm Use the cooling water in the drill to prolong the life of the drill bit. Recommended drill speed 250-400rpm. Spiral Cutter Flute: 135 Double point tip and double flute for self-centering and deburring. Spiral flute helps clear chips while drilling. Unique step design, one drill bit can be used to open holes of different sizes, means the equivalent of a drill box High-speed steel tools are good for most general purpose applications, offering a combination of hardness and toughness for wear resistance Multi-function, deburring, chamfering , expanding hole Material: HSS 4241 steel Type: Step Drill Quantity: 1PCS Color: Silver Item Size: 6-60mm: 12 steps (6mm, 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm) Package includes: 1 x 6-60mm HSS Step Drill Bits