Crimping: When can you use the Technique?


It is important to terminate the wires using plugs and connectors to make a cable harness. It would help if you crimped the ends with any crimping tool on hand. What is crimping, and how can you use it for a secure connection?

Table of Contents

What is Crimping?

Crimping is a solderless connection that terminates stranded or solid wires. Although you can use soldering as well, crimping is still preferred.

It is because the crimp can ensure a gas-tight locking that will prevent moisture and oxygen from entering the electrical connections. Moreover, the crimp joint gives a more robust joint to larger and smaller cables without any alloy.

Crimping is usually done by first putting the port into the crimping tool. The crimp barrel has to be the right size for the end of the wire. Then you will insert the cable into the terminal, and the end of the wire will be tight with the end of the terminal. Hence, it makes sure that the wire’s cross-sectional area is as big as possible. In the end, with the grips of the crimp tool, you will squeeze and change the shape of the terminal until it becomes cold-welded to the wire.

Connecting the wire may look slightly loose at the edges because this is good. After all, it will not have sharp edges that could cut the outside strands of the wire. If you do it right, the middle of the crimp will be flat or cold-formed.

Connectors also use more specialized crimp. For example, crimping of signal plugs on coaxial cables for applications that use higher radio waves. However, Crimped contacts stay in place (, you cannot disconnect and reuse the connectors and wire ends).

Theory of Crimping

Crimp the connectors by attaching the stripped ends to the connector. Then you can bend the end by pressing it firmly around the wire. Most electricians use an automatic crimping tool to do the job. These tools go by the name “crimping pliers.” It is because you will need a gas-tight finish on the crimped connectors.

Crimp connections that work well bend the material of the plug. When you compress the wire, there is a lot of stress around the metal. These forces work against one another while creating static friction that keeps the cable in place. Crimped connections are resistant to vibrations and heat waves.

There are two major classes of wire crimps that exists.

  • Open Barrel Crimps shaped like “V” or “U.” These crimps have metal ears that you can fold on the metal strands before attaching them to the terminals. Moreover, it is easier to use open barrel crimps since you do not need to shove all the metallic strands in a tight opening.
  • Close Barrel Crimps have a cylindrically shaped opening for the cable. When you insert the strands inside this opening and crimp it, you will see that the shape is deformed. In such a crimping operation, the wire becomes less resilient to vibration.

Crimp shapes

Some popular crimp shapes are

  • C Crimp
  • D Crimp
  • Crimp
  • F Crimp of B Crimp
  • W Crimp
  • Oval, Confined Crimp
  • Overlapping Crimp
  • Mandrel (crescent) Crimp
  • Four-Mandrel Crimp
  • Mandrel Narrow Crimp
  • Mandrel Indent Crimp
  • Hexagonal Crimp
  • Square Crimp
  • Tyco Crimp
  • Western Crimp
  • Trapezoidal Indent Crimp
  • Front Trapezoidal Crimp
  • Trapezoidal Crimp

Applications of Crimping

As an alternative to soldered connections, most electricians prefer using crimping methods. Although there is complex research to conduct while choosing a crimping method, still following reasons can aid you in your decision.

  • Which method is easier and cheaper to produce bulk crimps?
  • Is it dangerous to opt or harmless?
  • Can it give you superior mechanical strain and lay a strong foundation of connection?

Single-wire crimp terminals

Some single wire crimp terminals are

  • Blade or quick disconnect
  • Flag tongue
  • Hook Tongue
  • Spade’s tongue
  • Rectangular tongue
  • Ring tongue
  • Multiple Stud
  • Butt splice
  • Packard
  • Pin or wire pin.

Steps for Crimping a wire

Before starting the crimping process, you should have the crimp tool, terminals, wire stripper, heat shrink system, and a wire. After you get these things, you can follow the following process.

  1. Select the appropriate wire size. For that, you need to see its AWG marking. However, if there is no AWG measurement, you can always measure the size manually.
  2. Then, choose the crimp terminal as per your requirement. Keep in mind whether the terminal can endure moisture, current surge, or other physical factors.
  3. Now, select a crimping tool accordingly so that it can make a tight crimp on the wire.
  4. As you have done selecting, take the wire and strip its end. Then, insert the stripped end into the crimp while ensuring that all strands are inside the crimp hole. Now, press the handles of the crimper strongly and release when you feel the terminal has been fixed.
  5. In the end, take the wire out of the tool and fit a heat-shrink tube. Now, with a shotgun, fix the sleeve on the terminal, ensuring that it does not cover the end.

Multi-pin connectors

One way to join wires is to tighten them together. Depending on which side of the connector the pins are plugged in, they can be called front release or rear release.

  • Front release contacts are freed from the front corner of the plug and then removed from the back.
  • The rear release contacts are free and taken out from the connector’s back (wire side). The removal tool frees the connections from the back and drags them out of the holder.

How to Crimp Rj45

  • Strip the cable insulation one inch from the end using a stripping tool. Now, please remove the metal strands and unwind them to insert them into the connector later.
  • Arrange the wires into the right order of color and cut them in an even line, one and half-inch away from sheathing.
  • Now, hold the RJ-45 connector so that the pins are facing upwards. Insert these wires and let them get fixed into the small grooves inside the connector. 
  • Next, stick the end into the crimping tool and press it firmly. The crimping should fix the wires with the pins, making the path for a signal flow.

After these steps, you will get an RJ-45 cable. You can crimp it again with the crimping tool in case of any disconnected wire. 

How to Install Molex Connectors

  • First, strip the wire using the stripping tool and add an un-crimped power connector to the end.
  • Now, set the wires within the connector housing to be properly linked to the inner pins. 
  • Once you are confident, place the wire and connector inside a crimping tool and press firmly until you are sure about the perfect crimp.

Coaxial connectors

For coax, you can use wire strippers that remove the outer jacketing, shielding braid, and an inner insulating layer to the precise length in one go.

How to Crimp Coax

  • Strip the cable insulation from one end, exposing the metalcore.
  • Insert the wire to the back of the F connector and crimp it using the crimping tool. 
  • In the end, remove the finished cable from the crimping tool and screw the other part of the F connector to the cable.


Judging Crimp Quality

  • See that there aren’t any strands that have been bent so that they can cold flow into the connector’s body at the end.
  • The shell of the connector isn’t too twisted.
  • The cables are in good working order, with no scrapes, severing, nicks, or malfunctioning. 
  • Insulation is not pulled, twisted, ripped apart, faded, or charred.
  • There are no large spaces inside the crimp (there is no space for moisture or oxygen to enter the connector).
  • Wire has a large number of strands inside the connector. It is so that one or two disconnected strands won’t hurt the crimp density, making the connection less strong and more likely to break.


Crimping is essential to fix the connectors with the wire ends. You can use good quality crimping tools and methods for ensuring proper crimps. We offer wiring harnesses and cable assemblies with termination methods.