The Basic Oneway scroll chucks have a nickel-plated body, case-hardened base jaws and a scroll coated with a dry, long-lasting lubricant. Precisely made, the chuck body typically has less than 0.001" of runout; with the jaws mounted, runout can be expected to be less than 0.005". Due to their special construction, the jaws can be easily tightened on round or square stock. A stop pin prevents overextension of the jaws. Lever operated, the chuck weighs 4 lb.