Pliers

Pliers are a comparatively modern invention. Pliers are popular hand tools which are used for gripping objects by using leverage. They have a pair of pivoted jaws, used for holding, bending, turning, gripping or cutting a variety of things. They have different jaw configurations depending on their usages. Top quality pliers are forged from fine-grain tool steel, machined to close tolerances with hand-honed cutting edges properly hardened. They are polished, adjusted and inspected. Pliers vary in length from 4" to 20". Every tool user make use of pliers of various types.


Design
When we talk about the look of a plier, we can say that is probably started out looking something like our modern day barbeque tongs. The basic design of pliers has not changed much since their origin. The plier has a a pair of handles with the pivot which is often often formed by a rivet. The head section has the gripping jaws or cutting edges. Thereby, the plier consists of three elements—the handle, the pivot and the blades. In comparison to a pair of scissors or shears, the jaws of the plier always meet each other at one point.

How to use a plier?
Pliers convert a power grip into a precision grip. The power grip is the curling of the fingers into the palm of the hand and when we talk about precision grip, it means directing the power of the hand's grip on to the object to be gripped in a precise fashion. The handles are long compared to the shorter nose of the pliers. Hence, the two arms or the pair of handles act as first class levers with a mechanical advantage, which helps in raising the force applied by the hand's grip and forcing it on the work piece. Pliers are used when our fingertips can't do the job alone.

Materials
The materials used to make pliers consist mainly of steel alloys, like stainless steel, aluminum, carbon etc. There are some with additives like Vanadium, Chromium, which improve alloy strength. It also helps in preventing corrosion. The grip of the pliers sometimes have insulated grips. This not only prevents electrical conductivity but also ensure better handling.

Classification of pliers
Depending on the functions, pliers can be classified into four main groups:

• Gripping pliers: These pliers are used to improve grip and the most common type of pliers. Lineman's pliers, needle nose pliers, round nose pliers etc. are examples of gripping pliers.
  
  
• Cutting pliers: Cutting pliers are used to sever or pinch off. For example, lineman's pliers, pinching pliers, wire stripping pliers etc. are cutting pliers. Cutting Pliers are of three types:
  • Side Cutters have a cutting blade on one side only and are available in long, curved and short-nose types.
  • End Cutters have cutting blades on the end and are used to make sharp, clean cuts close to the surface on wires, bolts and rivets.
  • Diagonal Cutters have two cutting blades set diagonally to the joint and/or handles. Shears have cutting edges that pass each other.
    
    
  Some cutting pliers are made with a spring in the handle to open them automatically after each cut, providing ease and comfort for the user.
  
  
• Crimping pliers: Crimping pliers are special type of pliers used for crimping objects, which is not possible by other pliers.
  
  
• Rotational pliers: These type of pliers were specially developed by NASA engineers in order to help an astronaut to turn a nut in zero gravity.

Types of pliers
There are different types and sizes of pliers and each plier is designed for a specific purpose, although their versatility makes them suitable for many jobs.

Slip-joint pliers: Great for tightening, they are the most common type of pliers used in households, having a joint which can be used for two different width openings.		Groove-joint pliers: They are similar to slip joint pliers, having several joints to fit many jaobs of vaious sizes. They are also referred to "Channellock"
Needle-nose pliers: Used for reaching places with restricted clearance, these kind of pliers have a pointed nose and may have side cutters. Its typically used for all electrical and electronics work.		Diagonal cutter pliers: Diagonal pliers are actually cutting Pliers with cutters positioned diagonally to the handle to provide leverage when pulling cotter pins. These are also used for general cutting by electricians and mechanics.
Solid joint pliers: Solid joint pliers have a joint fixed with a solid pin or rivet and are not adjustable.		Lineman's pliers: Also known as combination pliers or electrician pliers, these are actually heavy-duty, side-cutting pliers, designed for all regular wire-cutting needs. These pliers have gripping jaws in addition to cutting edges. High-leverage lineman's pliers have rivet placed closer to the cutting edges to provide 50% more leverage.
Multiple slip joint pliers: This kind of a plier is a general utility tool with up to eight adjustments, allowing for jaw openings up to 4 1/2". It may be available in either multiple hole or tongue and groove types. Also, Straight and curved jaws are available, while the most common types is 10" water-pump pliers.		Plumber's Special Pliers: This kind of pliers are available with smooth jaws or jaws covered with a soft material to prevent scratching, when used on plated plumbing fixtures.
Parrot Nose Wrench Pliers: Noted for its grip, it is a combination pliers and pipe wrench with 75° offset nose. These kinds of pliers are ideal for pipe and tubing.		Thin Jaw Slip Joint Pliers: These pliers resemble slip joint pliers closely but are made with a slim nose to reach into tight places.
Curved Thin Needle Nose Pliers: With nose bent at about 80° angle, this kind of pliers are used for reaching round objects.		General Utility or Water Pump Pliers: These are all-purpose pliers with as many as five jaw-opening adjustments. Its teeth are shaped for positive grip on round objects.
Duckbill Pliers: Majorly used by jewelers, telephone workers, weavers, these pliers have long, tapered, flat nose for work in restricted places.		Wire Strippers: Featuring adjustable stops, Wire Strippers are used to cut insulation, without damaging wire.
Midget Pliers: Used by people working with small objects or in confined areas such as electronic technicians, hobbyists, electrical workers, aviation mechanics. Midget pliers include straight, chain, round, end-cutting, diagonal-cutting and flat-nose pliers in extra-small sizes.		End Cutting Nippers: Meant to ensure sharp, clean cuts close to the surface on wires, bolts and rivets, end-cutting nippers feature powerful leverage.