A pipe vice is a plumbing tool used to hold pipe or tubing securely so that it can be cut or threaded. Pipe vices are also useful for pipe welding. In a manufacturing environment, a pipe vice is a critical piece of apparatus in the assembly of pipeline components. A vise (American English) or vice (other English-speaking countries) is a mechanical apparatus used to secure an object to allow work to be performed on it. Vises have two parallel jaws, one fixed and the other movable, threaded in and out by a screw and lever.An engineer's vise, also known as a metalworking vise or machinist's vise, is used to clamp metal instead of wood. It is used to hold metal when filing or cutting. It is sometimes made of cast steel or malleable cast iron, but most are made of cast iron. However, most heavy-duty vises are 55,000 psi cast steel or 65,000 psi ductile iron. Some vises have a cast iron body but a steel channel bar. Cast iron is popular because it is typically 30,000 psi grey iron which is rigid, strong and inexpensive. The jaws are often separate and replaceable, usually engraved with serrated or diamond teeth. Soft jaw covers made of aluminum, copper, wood (for woodworking) or plastic may be used to protect delicate work. The jaw opening of an engineer's vise is almost always the same size as the jaw width, if not bigger.