CMT 392.200.11 Hinge Boring Bit, 20mm (25/32-Inch) Diameter X 5/16-Inch Parallel Shank 2-39/64-Inch Overall Length, Right-Hand Rotation Super-strength steel and cutter portion coated with black P.T.F.E. coating. Tungsten carbide tipped head with precision balanced center point. Ideal for hinges & blind holes. 2 precision ground cutting edges, 2 negatively ground spurs. Use on drilling machines, handheld routers in wood, wood composites and laminated materials.