BAMILL 4pcs 4-12/20/32mm Hex Shank HSS Nitrogen Step Drill Bit Set for Metal Drilling

Features: *Titanium coating reduces friction and heat. *High-speed steel pedal drilling is of higher quality and durable than ordinary twisted drilling. *These drill bits are perfect for creating smooth clean and round holes. Suitable for perforated metal iron aluminum brass wood plastic etc. *This drill set includes 3 sizes (4-12 mm 4-20 mm 4-32 mm) to meet your different needs. *Black is not a color treatment but a nitriding treatment to increase hardness and wear resistance. Notice: 1. Hand drills and bench drills can be used for these steps. 2. Water injection is used for cooling when drilling which can effectively extend the service life of the drill. 3. The recommended drilling rate is 250-400 RPM. 4. You can use our step drilling machine to drill holes within 5mm. Specifications: *Material: high speed steel *Surface treatment: Nitrogen treatment (increase hardness and wear resistance) *Handle shape: Hexagonal handle *Handle diameter: 6.35mm *Total length: 4-12mm length: about 67.7 mm / 3.45 inches 4-20mm length: about 71.6 mm / 3.61 inches 4-32mm length: about 102 mm / 4.80 inches Package Contents: 3*Step Drill Bit 1*Center Punch Note: 1.The real color of the item may be slightly different from the pictures shown on website caused by many factors.such as brightness of your monitor and light brightness. 2.Please allow slight error due to the hand measurement.