3/8"CD 13/64" Drill Hole Size. 7/8" Overall Length. The Type C countersink is designed for use in all woods, plastics, and non- ferrous metals. The countersink is held in place with 2 hex socket set screws fastened into the flutes of the drill. This countersink can be mounted on taper point, brad point, and regular point drills.\r\n