Carbide Tipped Brad Spur Drill bits are designed to create a very clean bottom hole most commonly used for inserting dowels. The drills have a 'W' tip that allows the outside spurs to shear the top surface as it cuts allowing a clean surface at the opening of the hole. All drills come equipped with a depth screw on the bottom of the shank and a flat for set screws to lock into. Coating on the fluting of the drill bits reduces the friction between the chips and the inside of the flute the help prevent burning of material. These drills can be used in a CNC machine with a drill adapter that converts the flat shank into a cylindrical shank.