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.