PURPOSE: To ensure the mounting of movable jaws on respective sliders and to quickly perform the attachment and detachment thereof by use of a threaded screw having a brake applied to one jaw slider in order to position the movable jaws for an asymmetric workstation.

CONSTITUTION: A wide-opening vise has two movable jaws 24, 25 and a fixed jaw 26, and the movable jaws 24, 25 can be easily removed from and reset to associated sliders 27, 28. The sliders 27, 28 have upwardly projecting bodies 101 having pressure release latches 105 for fixing the jaws in fixed positions of the sliders. A brake and off-set assembly is associated with one movable jaw. This combination structure allows the second movable, jaw, after the first movable jaw has engaged with a workpiece, to engage and disengage with from a workpiece without effecting the engagement of the first movable jaw with its held workpiece. At least two off-set positions are provided for the engagement and disengagement of the second movable jaw.