Jacobs 32283C 41BA-3/8-Inch Chuck 0.04-IN.~0.375-Inch Capacity Medium Duty Plain Bearing Keyed Chuck With 1/2-Inch 20 Threaded Mount T.I.R. 0.014-Inch maximum at half capacity 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