Cobalt Hard Straight Rod Twist Drill Model: M35 Cobalt 1.5-6.5mm 13-piece set High-grade M35 cobalt drill bit sets, which generally provide the best heat resistance, wear and chip resistance and long tool life. The three-stage design can increase the efficiency of drilling stainless steel, aluminum, copper, plastic and hardwood. High hardness The hardness can reach 64-68 degrees, suitable for stainless steel within 1-10mm This twist drill is typically capable of operating three to five times as fast. Although more expensive, the cost per hole is lowest when using a cobalt drill because it produces more holes. A sharp enough drill edge can cut metal material into long strips of iron filings, rather than slowly grinding the material with a blunt drill. Precautions: Twist drills have high hardness and are brittle, and there is a risk of breaking if they swing too much when drilling. Please pay attention to safety when drilling stainless steel and other thickened steel products. You can add water or coolant to cool down while drilling to reduce the drilling process. The high temperature generated in the drill will damage the drill bit. Set of 13 metal bits includes: 1.5mm 2.0mm 2.5mm 3.0mm 3.2mm 3.5mm 4.0mm 4.5mm 4.8mm 5.0mm 5.5mm 6.0mm 6.5mm The packaging includes: twist drill set of 13 Main points: 1. The size of the product is measured manually, there may be errors 2. Since different monitors display different colors, please refer to the real color you have received. 3. Please confirm the size before buying.