Vise-Grip® pliers are specially-designed pliers that are made to clamp the workpiece with a single squeeze of the tool by the user, eliminating the need to maintain a constant pressure on the pliers' handles. They’re found in practically every toolbox, regardless of whether their owner is a woodworker, mechanic, blacksmith or sheet metal worker. The tool was invented in the US by William Petersen, a Danish immigrant blacksmith, who used standard pliers to grip his workpiece with his left hand while hammering it with his right. What he wanted was a tool that would clamp like a vise, but with a pliers' one-handed operation. After some trial-and-error, in 1921 he invented Vise-Grip® pliers, which would exert a vise-like grip on a workpiece but didn’t require the time and effort of operation that a standard vise demanded.
Regular pliers and most variations consist of two identical handles with jaws at their ends; the handles are connected by a nut that acts as a fulcrum. When the handles are squeezed together, the jaws press against each other, gripping a workpiece or anything else between them. Some pliers include cutting blades in the jaw mechanisms, facilitating wire cutting. Hand pressure must be maintained to keep the workpiece secure, however; if pressure is relaxed, the workpiece might slip, and if pressure is released, the pliers will lose their grip altogether.
Pliers are used today primarily for turning nuts and grasping items. Before the invention of Vise-Grip® pliers, though, they were also used to hold workpieces when the use of a regular vise was impractical or impossible. Welding and riveting were just two of many such jobs.
Vise-Grip® pliers differ markedly from regular pliers. The two handles are not identical, and the thicker of the two is usually held uppermost in the user's hand. The distance between the jaws when in the “closed” position is regulated by a screw in the base of the thick handle. This is adjusted based on the size of the workpiece to be gripped; when properly adjusted and the jaws are squeezed onto the workpiece, the Vise-Grip® pliers grip and hold fast without the need for continued pressure on the handles. The original design required the user to pull the handles apart to release the grip, but in 1957, an "easy release" lever was added to the narrow handle that required only a slight squeeze.
Early production of Vise-Grip® pliers was slow due to the state of the American economy, the natural reluctance of workers to adopt a new tool, and the inventor's preference for keeping the entire operation small and manageable. Indeed, the tools were manufactured in Petersen's workshop until 1938, when a proper manufacturing facility was established in a closed-down drugstore. The company literally sold the tools door-to-door in Nebraska until it landed a contract with the US government in the opening months of World War II. American military production requirements over the next few years kept the company operating at full capacity and made the tools themselves enormously popular.
The basic design of the classic Vise-Grip® pliers has barely changed since the introduction of the easy release lever in 1957. Different sizes and shapes are available for the many different applications they're suited for, but the underlying concept remains the same. It wasn’t until the early 21st century, in fact, that changes were made to the Vise-Grip®. In addition to coating the handles with a foam cushion, the release lever was upgraded to a fast release feature that allows users both to grip and release with a single hand.