Big Horn 19163 Hex Shank Hinge Bits are self-centering, quick change bits that allow you to put your pilot holes where they belong: in the center of your hinges. Spring loaded self-centering bits mean less walking and more precise drilling. Set includes 3 sizes: 9/64", 7/64", and 5/64" and fit easily into most commercially made hinges. Bits are standard 1/4" hex shank, and allow for fast, easy quick change without re-chucking. Includes a replacement bit for each size and Allen Wrench. These highly accurate, self-centering hinge drilling hinge bits are used for precise drilling of holes for cabinet and door hinges, door butts, striker plates, window pulls and all large and small hardware. Desired depth is achieved by loosening a setscrew, setting the high speed drill bit, and then tightening the setscrew. Bit is Self-centering & accurate. Body has screw top for ease of cleaning & changing bit. Replaceable bits. Bodies are stamped with size. The spring loaded outer guide keeps drill centered for perfect pilot holes. Top unscrews for easy cleaning.