Medium Duty Plain Bearing Chucks, K32, 0.08 in-1/2 in Cap., Threaded 5/8-16 Fluted sleeve standard on all models except 6200, 6206, 6204, 6208, 31138, which are smooth and ground - For portable, bench, or floor mounted power tools - Jaws center-ground for absolute straightness and ...Medium Duty Plain Bearing Chucks, K32, 0.08 in-1/2 in Cap., Threaded 5/8-16 Fluted sleeve standard on all models except 6200, 6206, 6204, 6208, 31138, which are smooth and ground - For portable, bench, or floor mounted power tools - Jaws center-ground for absolute straightness and alignment - Jaws specially treated to ensure extended thread life and high gripping surface hardness - One-piece sleeve eliminates crack between driving teeth often found in other designs - Through-hardened sleeve teeth, nose, and keyholes for wear resistance