Carbide Tipped Hinge Boring Bits or Forstner Bits are designed for created larger recess holes typically for hardware hence the name Hinge Bit The bit’s geometry has a center point and edge spurs that give stability when making the recess allowing for clean, straight holes. The bit also includes a high setting screw on the bottom of the shank as well as a flat to help facilitate set screw clamping. These drills can be used in a CNC machine with a drill adapter that converts the flat shank into a cylindrical shank. For heavy production uses please see our Diamond Hinge Boring Bit