A chuck for use with a manual or powered driver having a generally cylindrical body having a nose section and a tail section, the tail section being configured to receive the drive shaft of the driver and the nose section having an axial bore formed therein. A plurality of jaws are movably disposed with respect to the body and in communication with the axial bore. A nut is rotatably mounted about the body and is in driving engagement with the jaws so that rotation of the nut in a closing direction moves the jaws toward the axis of the axial bore and rotation of the nut in an opening direction moves the jaws away from the axis. A shield cap is rotatably secured about the nose section of the body. The chuck also includes a first ring and a second ring, the second ring rotating relative to the nut over a limited arc. One of the first ring and the second ring defines a ratchet and the other of the first ring and the second ring defines at least one deflectable tab that is biased toward and engages the ratchet. |