Designed for precision grinding and inspection, the construction of these vises ensures workpieces are held perfectly square. To move the jaw, remove the screw using a _1/4" hex key (not included) and manually slide the jaw into position. Then replace the screw and tighten to firmly grip the workpiece. The base and three sides of the vise are ground flat to a parallel tolerance of 0.0002", enabling mounting on its base, either side, or upright. Mount through the base with screws or use setup clamps (not included). Vises can be used on Bridgeport-style milling machines as well as drill presses and surface grinders. They are also known as toolmakers’ vises.