AumoPro 3Pcs HSS Titanium Coated Step Drill Multi-Purpose Hex Shank High Speed Steel Hole Drilling Tool(For Metal Or Wood 3-12Mm/4-12Mm/4-20Mm)

AumoPro. Break, chamfer, cut or widen the hole. Support tools: Pistol drill, Hand drill, Rechargeable drill, Table drill. Attention. As the outer diameter of each step of the step drill is gradually enlarged, then the corresponding shear resistance and linear velocity will also be gradually increased. Since the step drill is completely dependent on the inclined edge, which is only 1mm in length, If the feedrate is too fast when drilling, it will easily be annealed due to bevel edge wear. Please give a downward force when drilling, do not press down too hard to avoid edge wear. Longs. 3-12mm length: 7.9cm/3.11". Length 4-12mm: Approx. 6.5cm 2.56". Length 4-20mm: Approx. 7.7cm 3.0". Hex handle diameter: 6.35mm. Break, chamfer, cut or widen the hole. Support tools: Pistol drill, Hand drill, Rechargeable drill, Table drill. Attention. As the outer diameter of each step of the step drill is gradually enlarged, then the corresponding shear resistance and linear velocity will also be graduall