Like screwdrivers, pliers are often thought to be fairly basic tools, but as with screwdrivers there are a substantial number of different models.
Each is designed for a different purpose and the best performance will be achieved by using the right plier for the job.
Pliers can be divided into two categories, one for gripping and twisting and one for cutting. A few models such as engineer's combination pliers combine both functions.
The quality features are well forged steel, the heat treatment to provide a positive cutting edge without making them brittle, the geometry of the jaws, a firm positive joint and, if required, good quality insulation.
The body and handles of all pliers should be hardened and then well tempered back. On cutting pliers the cutting edges are then induction hardened.
The geometry of the cutting edge is important, for the bigger the angle, the stronger the cutting edge, but the narrower the angle, the easier it is to cut.
The gripping plier needs to be able to hold the maximum capacity without the need to stretch the hand too wide.
Quality pliers must have a joint which is firm and does not wobble. A good way to test a pair of pliers is to try the joint for ease of use and lack of sloppiness.
Traditionally there are three main types of joints: box joints, lay-on joints and slip joints.
These are formed at the time of forging when one handle is literally forged around the other to provide a box joint traditionally considered to be the firmest.
As with other cutting tools, the cutting edges of pliers should not be twisted and the cutting pressure should always be straight and at right angles to the material being cut.
They have curved jaws to grip the cable and stop it being pushed out as pressure is exerted.
They come in two types, the standard cable cropper for cutting copper and aluminium cables, and standard cable and wire cutters for cutting heavy stranded cables, with rope and stainless steel rigging.
These are for removing nails. Although similar in shape to an end cutter, they are not as sharp, being designed to bite into and grip and draw nails and not cut through them.
The claw is for removing tacks.
The ball is traditional, one theory being that it was originally a snail horn countersink, but it is now taken to be for added comfort to the palm of the hand when using the pincer.
These are available in two types, for fitting or removing circlips. External open the circlip, internal close the circlip.
So called because they are a combination of gripping and cutting pliers. Often called engineer's pliers, or, if insulated, electrician's pliers, they are strongly made with flat serrated jaws for gripping flat surfaces and a rounded section in the jaws for gripping tubes and pipes. Behind the gripping section of the jaw are the cutters.
Also included in the main body of the pliers is a wire cropper for cutting thin wire and cable.
These are sometimes called side cutting pliers, and are for cutting wire. The cutting edge is at a slight angle to the handles to allow the user to cut close to a flat surface, and leave the hand clear.
These are designed for regular frequent use, often on production line and often for cutting thin gauge but very tough electronic wire.
There is sometimes confusion between electronic pliers and instrument pliers. This is probably because they are both small (approx. 41/2in long).
The electronic plier is more expensive because it is more robust and usually subjected to much greater production line use.
These are sometimes called top cutting pliers, but are also used for cutting wire. The cutting edge is at 90° to the handle, allowing very close cropping of wire.
Failed to find Class
These pliers, sometimes known as square nosed, duckbill or pendulum pliers, have flat serrated jaws, designed for lightweight work and working in narrow crevices.
These have two curved sections in each jaw to grip pipework of different sizes. They also have a 'V' notch in the front end of each jaw to grip wire. The ends of the handles are shaped to form a pipe reamer and turnscrew respectively.
Glaziers' Or Glass Pliers
These have wide flat jaws for gripping glass up to a cut line for breaking off narrow strips.
These are for small delicate work and are often used by model makers and jewellers.
These should have properly tested heavy-duty insulated handles. The user should be particularly careful to check that he or she is using a proper pair of insulated pliers and is not confusing insulation with plastic sometimes applied for comfort on noninsulated pliers. These are sometimes called velvet grips.
Only genuine approved pliers conforming to DIN EN60900 or VDE 0680-2 should be used on electrical work.
Lay-on joints, sometimes called lap joints, are formed by one handle being laid onto the other and riveted.
Recent developments have meant that very high quality results can be achieved with lay-on joints, provided that the rivet is strong, well fitted and of the correct shape in order to provide a very firm hold.
Top quality lay-on joints are now considered up to the standard of box joints which are now seldom made.
Round Nosed Pliers
These have a pair of smooth conical jaws to form loops and work generally with wire or thin strips of metal.
Self Grip Pliers
These are controlled by a screw at the handle so that the jaws grip with a spring action and hold the work firmly until they are released by means of a lever. Often described as gripping wrenches or self-locking wrenches.
These are forged similarly to lay-on joints except that the hole for the rivet is elongated and the rivet not tightened so that the two halves can be opened further to provide a wider jaw opening.
Snipe Nosed Pliers
These are sometimes known as needle nosed, long nosed, chain or radio pliers. They are made in a variety of shapes with different length jaws and in some cases with the jaws bent, but all have serrated jaws.
Some models have side cutters to crop soft wire. All jaws are tapered to work in confined spaces.
These are fitted purely for comfort. The user should be particularly careful to note that the velvet grip is not insulated and should not be confused with an insulated plier.
Used originally to work on plumbing fittings, they have serrated jaws to grip round objects, a loose joint to allow slip to usually four different jaw openings, thin jaws to enable entry between tap covers and long handles for good purchase.