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All about Pliers

Mechanical Skills: Chapter 5

Pliers - Part 1

By the end of this module you will be able to

- Understand what pliers are, and

- Use different types of pliers Skip to quiz!


Pliers are a hand tool used to strongly grip various types of objects. Pliers can be used to grip

nuts, hold onto objects, strip wire, and a lot more! The versatility of pliers makes them one of the most common tools you will use.

All pliers have two parts:

  • A jaw, and

  • A handle

The handle can be open or closed to change the width of the jaws. The jaws are used to clamp or grip objects.

Types of Pliers

There are several types of pliers. Types of pliers include:

  • Needlenose pliers,

  • Linesman pliers

  • Side cutters, and

  • Slip joint pliers

Needle Nose Pliers

The first type of pliers we will look at are needle nose pliers. Needle nose pliers have a head with long pointy jaws. The long jaws allow you to reach farther objects. The long jaws are also more precise.

To use needle nose pliers, you start by moving the handles. As you pull the handles away from each other, the jaw size will increase. As you push the handles towards each other, the jaw size will decrease.

If you want to grab an object with needle nose pliers, you will start by pulling apart the handles. Position the object between the jaws. Close the handles. Hold the handles closed with one hand. The jaws of the pliers should be tightly gripping the object.

One of the best uses of needle nose pliers is to grip and bend wire. To grip wire, hold the wire inside the jaws of the needle nose pliers. To bend wire, hold the wire in the jaws. Twist the pliers in the direction you wish to bend the wire.

Needle nose pliers should not be used when you need a very strong grip. Needle nose pliers have thin narrow teeth that can easily be damaged or bent out of shape.

Linesman Pliers

Linesman pliers have an oval shaped head with flat gripping jaws at the nose tip. Linesman pliers are commonly used to cut, strip, and bend wire.

The jaws of linesman pliers have three parts. The tip of the jaws are great for gripping wire. The middle segment of the jaws are used to grip circular objects like the heads of bolts.

The bottom segment of the linesman pliers have sharp edges on each jaw. The bottom segment is used to cut or trim wire.

To grip an object, you will follow the same process as the needlenose pliers. To bend, twist, or straighten wire, gently grip the wire with the first segment of the jaws. Turn the pliers in whatever direction you wish to shape the wire.

To grip a bolt or nut, you will use the middle segment of the jaws. To grip a bolt, place the circular area of the jaws around the bolt and squeeze the handles together.

To cut wire, place the wire in the bottom of the plier jaws. Squeeze the handles of the pliers together and the jaws will cut the wire.

Side Cutter

Side Cutters have a very sharp jaw. You can think of side cutters as very strong scissors. Side cutters can cut electrical wire and strip insulation off of wire.

To cut wires, place the wire or screw inside the jaws of the side cutters. Squeeze tightly until the wire is cut.

Recall that wires have a rubber sheath, called insulation, around the copper. To trim the insulation, place the wire in the jaws of the side cutter.

Instead of pressing down until the wire is cut, press down until the jaws have a firm grip on the insulation. Pull the side cutters and wire in opposite directions. When you do this, the insulation will be pulled off the wire.

Slip Joint Pliers

Slip Joint Pliers are similar to the pliers we have covered so far. Slip joint pliers have a joint that you can adjust to change the jaw size. You can see the joint in the image to the right.

When you fully open the handles of the slip joint pliers, the screw will switch to the second joint position. The second joint position makes the jaws wider. This can be helpful if you are trying to grip a larger object.

The head of a slip joint plier is similar to the linesman plier. There are three parts to the head. The top part is for gripping wire. The middle part is used for gripping bolt heads. The bottom part can be used to cut wire.

Pliers are a quick and easy way to strongly grip certain objects. Knowing which pliers to choose and how to use them leads to completing jobs in a fast and effective manner.

There are many types of pliers including:

  • Needlenose pliers,

  • Linesman pliers

  • Side cutters,

  • Slip joint pliers


Pliers - Part 2

By the end of this module you will be able to

- Use more types of pliers, and

- Use pliers safely Skip to quiz!

Types of Pliers

This module will cover additional types of pliers like:

  • Wire strippers,

  • Wire crimpers, and

  • Channel lock pliers

Wire Stripper

Stripping a wire is the process of removing the plastic insulation from electrical wires. Wire strippers are pliers designed to remove the insulation from wiring. The jaws have several holes in the center of them. Each notch is designed to strip a specific sized wire.

Wires come in multiple sizes. We measure wire by “gauge”. Gauge measures the diameter of wire. The lower the gauge, the larger the wire is. For example, 4 gauge wire is larger than 10 gauge wire.

To strip wire, you need to know the size of the wire. For example, 10 gauge wire. Insert the wire into the correct sized notch on the blades of the wire stripper. For example, a 10 gauge wire would go in the hole marked 10.

Squeeze the handles of the wire stripper so it is tight around the wire. Rotate the wire strippers around the wire so the insulation gets cut. Pull the wire away from the wire strippers while still squeezing the handles. The insulation should be removed.

Wire Crimpers

Crimping is the process of squeezing two objects together to combine them. Wire crimpers can cut and strip wire but they can also connect pieces of wire by crimping terminals. Just like wire strippers, wire crimpers have slots for different sized wires.

Place your wire into the correct stripping hole. Remove the insulation from the wire. Insert your wire into the terminal so the ends of the wire are exposed. Crimp down on the wire and terminal with your wire crimpers. This should connect the terminal and the wires.

Pull the connector to make sure the connection is solid. If you can pull the connector off by hand, the connection was not strong enough and needs to be redone.

Pump/Channel Lock Pliers

Channel lock pliers, also called tongue and groove pliers, have an angled head. Channel lock pliers have two jaws:

  • An adjustable jaw, and

  • A fixed jaw

The adjustable jaw can change position. The fixed jaw is set in one place.

The fixed jaw is set at an angle of 45° to 60° and does not move when adjusting the handle. The adjustable jawcan move up and down a grooved channel to change the jaw size.

Channel lock pliers work in a similar way to the slip joint pliers we discussed previously. As you open the pliers, you can move one handle into different grooves. Moving the handle to a new groove changes the width of the adjustable jaw.

Channel locks are great for holding irregularly shaped objects. They are commonly used to help tighten or loosen piping. Channel locks can also grip nuts, bolts, and other objects.

To use channel lock pliers, you need to change the adjustable jaw size to fit the object. Open the handles and slide the adjustable jaw into the required groove. With the handles still open, place the object within the jaws of the pliers.

Close the handles of the pliers until the jaws have strong contact with the object. Grip the handles shut so you have a secure connection to the object.

The adjustable jaw on channel lock pliers have angled teeth. When using channel locks make sure the teeth of the adjustable jaw turn into the object you are turning. This helps prevent the teeth from coming loose or getting grinded down.


Pliers can strongly grip objects, but they should not be used on all objects. Do not use pliers on large nuts or bolts. For large nuts or bolts, a wrench is a better option. Do not strike objects with your pliers. It is better to use a hammer to strike objects.

Do not use pliers to cut a live wire. Always check that the power is off before handling wiring. Do not use lightweight pliers to bend heavy wire. This can damage the teeth of the pliers.

When using pliers make sure to wear the proper personal protective equipment (PPE). Safety glasses, safety shoes, and gloves are important forms of PPE.

You learned how to use more types of pliers like:

  • Wire strippers,

  • Wire crimpers, and

  • Channel lock pliers

You also learned how to safely use pliers.


Question #1: What are linesman pliers used for?

  1. Straightening wire

  2. Cutting wire

  3. Bending wire

  4. All of the above

Scroll down for the answer...

Answer: All of the above

Linesman pliers have sturdy jaws to bend and straighten wire. They also have sharp edges near the bottom of the jaws to cut wire when needed.

Question #2: Which gauge of wire is the largest?

  1. 8 gauge

  2. 12 gauge

  3. 6 gauge

  4. 4 gauge

Scroll down for the answer...

Answer: 4 gauge

The smaller the gauge of wire, the bigger in diameter it is.

Question #3: When crimping a fitting to the end of a wire, how do you know that it is properly attached?

  1. You pull on the fitting and it doesn’t come off.

  2. You can’t see any wire coming out of the fitting.

  3. You test it on some electrical equipment.

  4. You pinch the crimp to see if it is deep enough.

Scroll down for the answer...

Answer: You pull on the fitting and it doesn’t come off.

Test your crimps by lightly pulling on the wire to make sure it does not come out.

Question #4: Which is a safe way to use a pair of pliers?

  1. Using your pliers as a hammer.

  2. Using pliers on smaller nuts.

  3. Cutting a live wire with pliers.

  4. Using pliers to bend heavy wire.

Scroll down for the answer...

Answer: Using pliers on smaller nuts.

Pliers can be used for light force jobs. Wrenches should be used to tighten and loosen larger nuts.


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