Abstract: Each of the jaws of a sliding jaw chuck are moved between workpiece clamping and release positions by a post, the end of which, in active position, is seated in an opening in an octogonal plate seated in a recess in the jaw. The plate is octagonal and its dimensions are such that it always entirely occupies the recess in the direction of movement of the jaw. In contrast, the recess is wider than the plate, permitting the plate, after removal from the recess, to be rotated about the post to any one of five positions. While the plate is symmetrical about its geometric center, the opening for the post is offset from the plates's center which results in changes in the spacing between the post and the ends of the recess, which controls the radial position of the jaw with respect to the axis of rotation of the chuck and thus the size of the workpiece which it can clamp.

Abstract: A chuck having a sliding outer jaw is locked against any adjustment in radial position relative to the inner jaw on which it is moved radially by a radially movable pin which, in one radial position, prevents axial retraction of the post interconnecting inner and outer jaws for radial movement. The chuck utilizes a tool having a pair of radially movable means, one of which is capable of moving the post axially of the chuck after the other means has caused the post retention to be made inactive for preventing axial movement of the post.

Abstract: A chuck support base for very accurate machining of parts includes a pair of interengaging members through which rotary motion is delivered to a tool holding chuck. The member on which the chuck is mounted has a ring with an internal frusto-conical exterior surface of a drive member mounted on the chuck support base of a machine tool. Both the ring and the driver member are secured to their supporting members by a bonding agent which initially is liquid and hardens while the structure to which it is attached is rigidly supported in a jig so that any variation from total concentricity with the axis of rotation of the tool is eliminated by compensating the positioning of the two rings before the bonding agent sets.

Abstract: A chuck is disclosed which has article gripping member each having a pivot portion intermediate its ends about which the member pivots as the chuck is opened and closed. The members are each caused to pivot by a pin which passes through a slot in the member adjacent the inner end of the member remote from the workpiece gripping outer end thereof. Movement of the pin lengthwise of slot causes the member to pivot. The slot in which the pin is seated is elongated lengthwise of the member and is inclined to the central axis of the member at a very minor angle whereby the centrifugal forces generated by operation of the chuck cannot generate sufficient force to cause the pin to move lengthwise of the seat and thus permit the jaw to release the workpiece.