1-piece fluted sleeve construction. Ball trust bearing reduces friction in chuck closing mechansim. Through-hardened sleeve teeth, nose, and keyholes for wear resistance. Maximizes gripping force and drilling accuracy. Treated to ensure thread life and high gripping surface hardness. Jaws center-ground for absolute straightness and alignment. For heavy-duty, close tolerance production drilling. For production drilling equipment, jig borers, milling machines, lathes, and radials