Abstract: A machine vise is provided with a body having a fixed jaw and a movable jaw which may be moved toward the fixed jaw by means of a tractively acting hollow screw spindle. A force amplifier is arranged below the fixed jaw and is operable by a pushing rod shiftably inserted in the hollow screw spindle. A common driving device rotates the screw spindle into and away from its clamping position. Upon a predetermined clamping force being exceeded the force amplifier is activated by the pushing rod. The movable jaw may be split in upper and lower portions.