Locking Pliers
Pliers that can be locked into position using an adjustable screw, commonly referred to by the brand name Vise-Grips.
Locking pliers, universally referred to by the brand name Vise-Grips, are hand tools that can be locked into a clamping position using an adjustable screw in the handle and a toggle lever. This locking mechanism allows the user to apply massive clamping force to a fastener or metal component, maintaining the grip without requiring continuous hand pressure.
In automotive diagnostics and repair, locking pliers are the tool of last resort for gripping stripped bolts, rusted exhaust fasteners, and rounded-off nuts. They can also be used as temporary clamps to pinch off rubber hoses (like vacuum lines or fuel lines) or to hold components in alignment during welding. However, because the hardened jaws feature sharp teeth, they will mar or damage the surface of any metal bolt they grip.
Symptoms of rounded fasteners that require locking pliers include slippage when using standard warranties. When using locking pliers on a bolt, the user adjusts the screw until the jaws close tightly on the fastener, then squeezes the handles until the mechanism snaps locked. Once the fastener is removed, it must be discarded and replaced with a new bolt.