A vise jaw is the adjustable teeth portion of a clamp where items are firmly held. The surfaces of a vise jaw are commonly scored or covered with plastic pads to grip objects as well as possible. Most vises are clamped or bolted onto a work bench to keep the jaws stable while in use. Vise jaws close and open when an internal treaded cylinder spins as the crank is turned clockwise and counterclockwise. Squeezing an item between the vise jaws may deform it if the crank is not turned carefully.
Some vise jaws are completely replaceable. Over time the thick metal plates from both sides of a vise jaw can get bent and worn to the point where they no longer meet up evenly when the closed vise is empty. Forward thinking designers have made it possible to simply unbolt and remove the plates themselves. Replacement vise jaw plates can usually be ordered directly from the original manufacturer or custom made from aluminum block. The cost of replacing the plates is generally much lower than the price for an all-new vise.
Vise jaw pads come in a wide variety of sizes and styles to fit almost any vise. The pads protect the vice jaw's metal surface and increase traction. Soft rubber pads flex to hold objects in the vise jaw without scratching or denting them. Harder plastic and vinyl vise jaw pads are often more durable than soft varieties and usually have a highly texturized surfaces. Pads are generally custom fitted to the jaws of the vise they are intended for so they can quickly slide in and out of position for intermittent use.
Lubrication is essential to the operation of vise jaws. The moving parts of a vise often operate within very limited tolerances. Small particles of sand and grit may make it difficult to turn a vise crank and close the jaws. Once the vise jaws are opened completely, a thin layer of grease can be applied to the threaded cylinder. Cranking the jaws open and closed a few times distributes the grease throughout the mechanism.
Angled and specialized vise jaws are used in industrial assembly-line vises. A slanted vice jaw holds a series of objects uniformly at a desired angle for precision manufacturing. Pressure-sensitive vise jaws relay force readings to a display. The sliding vise jaw is an adjustable style commonly marked with measuring increments.