It is more precise and safer to use these drill sets in the drill press. The tip is specially designed for drilling holes cleanly and is perfect for drilling hidden hinges and door locks. The head is designed with arc shape, which can remove debris and provide high working efficiency. The cutting edge is sharp, the positioning is precise, the hardness is high, the precision is high, and the cutting is stable. The drill bit can drill a clean flat bottom hole without chipping. High quality alloy blades, hardened, tempered and carbon HSS steel structure make the blades sharper and more durable. More fluid and less noisy. The knives are painted, waterproof and anti-corrosion. Suitable for making holes in wood. Precision grinding is suitable for mass use and easy to resharpen, they can easily enlarge existing holes and can drill any arc. It can be used to punch wood products, fix goals, drawers, plastic products, wood, plywood, etc. Suitable for pistol drills, bench drills, vertical drills, portable electric drills, vertical electric drills and magnetic walking belt drills, etc. (zhongchengdaye)