Diagonal pliers
Diagonal pliers or wire cutters or diagonal cutting pliers, are wire-cutting pliers (though they are not used to grab or turn anything, but are used to cut wire). They are sometimes called side cutting pliers or side cutters, although these terms are shared by other pliers designs and may lead to confusion. The plane defined by the cutting edges of the jaws intersects the joint rivet at an angle or "on a diagonal", hence the name. Instead of using a shearing action as with scissors, they cut by indenting and wedging the wire apart. The jaw edges are ground to a symmetrical "V" shape, thus the two jaws can be visualized to form the letter "X", as seen end-on when fully occluded. The pliers are made of tempered steel and inductive heating and quenching is often used to selectively harden the jaws.
Dikes — as in the phrase "a pair of dikes" — is jargon used especially in the electrical industry, to describe diagonal pliers. It is a portmanteau of "diagonal cutters". Dike can also be used as a verb, such as in the idiom "when in doubt, dike it out." This implies that a problem can be simplified by eliminating the unnecessary. In the United Kingdom and Ireland, they are commonly referred to as snips.
Applications
The handles of diagonal cutting pliers are normally insulated with a dip-type or shrink-fit electrically-insulating material usually rated at 1000 volts making them suitable for safe live line work. Even so, most carry a warning not to use for intentionally cutting live wires.
Diagonal pliers are useful for cutting copper, brass, iron and steel wire. Lower quality versions are generally not suitable for cutting tempered steel, such as piano wire, as the jaws are typically not hard enough. Attempting to cut such material will usually cause indentations to be made in the jaws, or a piece to break out of one or both jaws, thus ruining the tool. However higher quality side cutters can cut hardened steel, such as 2 mm piano wire.
For electronics work, special diagonal cutters that are ground flush to the apex of the cutting edge on one side of the jaws are often used. These flush-cutting pliers allow wires to be trimmed flush or nearly flush to a solder joint, avoiding the sharp tip left by symmetrical diagonal cutters.