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Crimping Pliers.

Types of Crimping Pliers

There are two generic types of crimping pliers; hand and ratchet crimping pliers.


Hand crimping pliers

As you can see from the picture below, hand crimping pliers are similar to combination pliers. The jaws feature a series of special profiles designed to squash (deform) the crimp connectors in the best way for secure wire connection.

The drawback with these types of pliers is that the pressure applied to deform the crimp is directly related to the strength of the person squeezing the pliers together – this could lead to insecure joints which can be a major fire hazard.


When quite a number of crimps need attaching, you can imagine that there would be inconsistent results and the last crimp may not be as secure as the first due to fatigue.

For repetitive work, consistency is very important and this is where ratchet crimping pliers are ideal.

Ratchet crimping pliers

Ratchet crimping pliers are designed to ensure safe, consistent and precise crimping of wires into crimp connectors.

So how do they offer consistency? - Ratchet crimping pliers use a ratchet deadlock system which means that the pliers must be fully closed, before they can be opened again.


They are factory set which makes sure that the correct pressure is applied to make a safe crimp.


Once the pliers have been fully closed and the crimp is complete, a quick release lever is activated opening the pliers ready for the next crimp.


Ratchet crimping pliers have hardened steel inserts screwed into the jaws of the pliers. These are often referred to as dies.

The crimp shapes in the dies are specially designed to deform the crimp in the best way for secure wire connection so it is important to match the right pliers to the terminal types being used.


In the picture opposite you can see that each of the dies is colour coded – this corresponds to the colour coding for insulated crimps, so selecting the right die is straight forward.


It’s not so straight forward for un-insulated crimps and boot lace ferrules as there is no colour coding, so care has to be taken to match the right die to the size of wire/crimp connector being used.

To help, each of the die positions in the jaws are marked with the cross sectional area of the wire that they are designed to work on – so, care has to be taken that the correct size crimp connector is selected and used in the appropriate sized die.


Remember, loose wires are a major cause of electrical fires, so using the right tool for the job is vital.

But it is not only crimp connectors for electrical wires that we need to concern ourselves with. Almost every modern building has Tele-communications and Data-communications facilities of some sort. This means that coaxial cables for sound and picture transmissions and data communications cables for computers are commonplace, all of which need to be connected to some piece of equipment. It is vital that the connections are secure otherwise all sorts of problems can be created.

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