IVY Classic 09050 1/2-Inch M2 High Speed Steel Countersink, 5 Flute, 82-Degree Point, 1/Card Precision-ground 82-degree point for countersinking into most Machin able metals, wood and plastic Hardened and tempered M2 High-Speed Steel, Premium Swift Bore (Registered Trademark) Designed with five flutes for chatter free smooth drilling, chamfering and deburring Creates a conical shaped recess to seat flat and oval-head screws Diameter: 1/2-inch, Overall Length: 2-1/4-inch, Shank: 1/4-inch round shank