High Quality: Using high-speed steel drill bit, high strength and hardness, durable in use and superior drilling performance, serving as a guide to center the guide holes needed for the hinges. < p>Appropriate Design Double-sided hole design Quickly and automatically discharge the sawdust from the hole on both sides without blocking the drill. This saves your time when removing sawdust. Easy Installation: Unique design and perfect punching effect. Applicable to the installation of a door hinge. Easy to use and install, quick change of bits, loading and unlocking with one hand. MultifunctionalApplicable to furniture, kitchens, woodwork, window doors, etc. Woods of different hardnesses require different self-centering drill bits. Simply disassemble the screw and replace the bit with a new one. With four bits4 bits of the most common sizes for woodworkers: 5/64", 7/64", 9 /64" and 11/64"1 Allen Key; Product Description Technical Data: Product Name: Hinge Drill Set< /p> Colour: Silver Material: HSS Product Name: Hinge Drill Set Colour: Silver Material: HSS Size: 5/64'', 7/64'', 9/64'', 11/64'' 5/64' ': The diameter of the hole is about 2 mm. Use a threaded screw of approximately 2.2 - 2.8 mm 7/64'': The diameter of the hole is approximately 2.8 mm. Use a threaded screw of about 3 - 3.5 mm 9/64 '': The diameter of the hole is about 3.5 mm. Use a sheet metal screw of approximately 4 - 4.5 mm 11/64'': The diameter of the hole is approximately 4.5 mm. Use a threaded screw of approximately 5 - 5.5 mm 1. unique design, perfect perforation effect. Easy to use and install, quick bit change, one hand loading and unlocking 2. sizes 5/64", 7/64", 9/64", 11/64" for carpenters, joiners, furniture makers and other woodworkers. 3.The sawdust is automatically discharged through the top of the holes on both sides without blocking the drill. 4. Perfect carpentry tool for woodworking, installing hinges on wooden doors, cabinets, windows, etc.