Center cutting Counterbore Cutter - 9/16in. Diameter / 1/2in. Shank, use with 10 Series Anchor Fasteners.Designed to machine most materials of medium hardness such as aluminum. The large core diameter provides rigidity and reduces deflection while the cutting geometry allows for rapid stock removal. They can be used for general-purpose milling including profiling and open-ended slots and keyways. High speed steel 2 flute Single end mill.