HSS Single Flute Countersink 5/16" Enables burr-free deburring and countersinking. Eliminates deburring and countersinking problems on aluminum, brass, bronze, plastics, rubber, soft steels, wood and other materials. Features include... Size: 5/16" Shank Diameter: 1/4" Overall Length: 1-1/2" Available in 60°, 82°, 90°, & 100°. Please select angle when adding to your cart.