Abstract: A clutch-brake unit for a mechanical drive, such as used on a press, has a hub which fits over a spindle at the end of a driven shaft, which may be a crankshaft, and locates against a flange on the driven shaft, thereby enclosing the entire spindle. The hub has a flange portion which carries an annular piston, and the chamber in which this piston is located is in communication with the hub interior. The hub has a drive disk mounted on it by machine screws that extend axially through the drive disk, the flange portion of the hub, and thread into the flange on the driven shaft so as to secure the hub to the shaft. The drive disk is spaced from the flange portion of the hub, and interposed between the two is a brake disk, a pressure plate, and a transfer disk. The brake disk is connected to an anchor attached to the press frame, and the pressure plate is spring loaded so as to urge the brake disk against the flange portion of the hub and thereby impede rotation of the hub.