Abstract: A chuck including a cylindrical body with a nose section and a tail section, the nose section having an axial bore formed therein. A sleeve is rotatably mounted about the body. Rotation of the sleeve in a closing direction moves the jaws toward a longitudinal axis of the axial bore and rotation of the sleeve in an opening direction moves the jaws away from the longitudinal axis. An O-ring is disposed adjacent the sleeve in a plane that is transverse to the longitudinal axis. A bearing has a first race adjacent the body, a second race adjacent the sleeve and bearing elements therebetween. One race defines a ratchet and the other of the first race and the second race defines a pawl biased toward the ratchet. The O-ring biases the pawl toward the ratchet and when the pawl engages the ratchet prevents the second race from rotating in the opening direction with respect to the first race.