Jacobs Chuck taper mounted heavy duty plain bearing chuck. Jaws center-ground for absolute straightness and alignment. One-piece sleeve eliminates crack between driving teeth often found in other designs. Through-hardened sleeve teeth, plus hardened nose and keyholes provide outstanding wear resistance. Each chuck 100 percent inspected for performance and precision. T.I.R. 0.004-inches maximum at half capacity. 3-11/16 inches closed length, 2-7/8 inches open length. 2-19/64-inches sleeve diameter.