Pliers are a hand tool used to hold objects firmly, for bending, or physical compression. Generally, pliers consist of a pair of metal first-class levers joined at a fulcrum positioned closer to one end of the levers, creating short jaws on one side of the fulcrum, and longer handles on the other side. This arrangement creates a mechanical advantage, allowing the force of the hand's grip to be amplified and focused on an object with precision. The jaws can also be used to manipulate objects too small or unwieldy to be manipulated with the fingers.
There are many kinds of pliers made for various general and specific purposes.
As pliers in the general sense are an ancient and simple invention, no single point in history, or inventor, can be credited. Early metal working processes from several millennia BCE would have required plier-like devices to handle hot materials in the process of smithing or casting. Development from wooden to bronze pliers would have probably happened sometime prior to 3000 BCE. Among the oldest illustrations of pliers are those showing the Greek god Hephaestus in his forge. Today, pliers intended principally to be used for safely handling hot objects are usually called tongs. The number of different designs of pliers grew with the invention of the different objects which they were used to handle: horseshoes, fasteners, wire, pipes, electrical and electronic components.
The basic design of pliers has changed little since their origins, with the pair of handles, the pivot (often formed by a rivet), and the head section with the gripping jaws or cutting edges forming the three elements. In distinction to a pair of scissors or shears, the plier's jaws always meet each other at one pivot angle.
The materials used to make pliers consist mainly of steel alloys with additives such as vanadium or chromium, to improve strength and prevent corrosion. Often pliers have insulated grips to ensure better handling and prevent electrical conductivity. In some lines of fine work (such as jewellery or musical instrument repair), some specialized pliers feature a layer of comparatively soft metal (such as brass) over the two plates of the head of the pliers to reduce pressure placed on some fine tools or materials. Making entire pliers out of softer metals would be impractical, reducing the force required to bend or break them.
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