A machinist vise is a heavy duty vise made of metal. It is attached to the top of a workspace, unlike a woodworking vise, which is attached to the side. A machinist vise is also called an engineer's vise, metalworking bench vise or fitter's vise, and in British English, it is spelled "machinist vice." Using a vise adds a greater degree of safety because the craftsman can work on an object without holding it.
The basic vise has a stationary jaw, a movable jaw and a screw to adjust the movable jaw. The jaws are screwed together to hold an object. The typical machinist vise jaw is 3-8 inches wide (about 7-20 cm). By comparison, a woodworker's vise is much wider, typically 7-10 inches (about 17-25 cm).
The jaws of the vise might be lined with wood or plastic to avoid damaging the object. Some jaws have a rough lining to prevent slippage. Other jaws are designed to hold a variety of shapes.
There are two main differences between machinist vises and other vises: thick metal construction and the mount. A machinist vise is mounted with bolts to the top of a worktable. Its heavy metal construction gives it the ability to tolerate repeated, heavy strain. Depending on the base, a machinist vise might have multiple functions.
The advantage of a fixed base is improved stability, but a swivel base is appropriate when the machinist vise will be used for a variety of projects. A swivel base can be turned 360 degrees, allowing the object to be rotated in any direction. Some machinist vises also have an angle rotation so that an object can be held diagonally instead of vertically.
Although commonly used when working with metal, the machinist vise can also be used to stabilize many types of materials. It can be used in sawing, drilling, sanding or gluing projects. Variations in its bases and jaws make it a very versatile tool.
Machinist vises are not to be confused with machine vises. A machine vise is mounted to a machine and normally used in industrial manufacturing settings. It often has a computer-controlled hydraulic or pneumatic release system for its jaws. A machinist vice is manually operated and typically used in a private workshop.