A machinist vise is a tool used to securely hold workpieces in place during machining operations. It typically features two parallel jaws, one fixed and one movable, allowing for precise clamping of various materials like metal or wood. Machinist vises are commonly mounted on workbenches or milling machines, providing stability and support while cutting, drilling, or shaping. These vises come in various sizes and designs, including bench vises and precision vises, catering to different machining needs. The jaws can be adjusted using a screw mechanism, ensuring a firm grip without damaging the workpiece. Proper use of a machinist vise enhances accuracy and safety in machining tasks.