How to use crimping tools

Crimping tools are tools used to connect wires to crimp terminals or sleeves, and are essential for electronic device detailing and installation work. There are several types of crimping tools, which can be categorized according to their applications and uses.

Uses of crimping tools

Crimping tools are used to crimp and connect wires to terminals. They are used in a wide range of situations, including wiring for equipment and indoor wiring work.

Crimping tools can be classified into four categories based on the method of use and mechanism of operation: manual one-hand tools, manual two-hand tools, manual hydraulic tools, and electro-hydraulic tools. Note that there are two types of manual one-hand tools: one for bare crimp terminals and sleeves, and the other for ring sleeves.


How to use crimping tools

Crimp tools are tools for detailed work, so it is important to follow correct usage carefully. Below are some points when using crimping tools. 

Confirmation of dimensions and range of use

The die to be tightened should be used in a position that conforms to the nominal dimensions of the terminal. Also, check the instruction manual for the tool and perform crimping work within the applicable range.


Insert the terminal into the wire that has been stripped of its insulation. The wire core should protrude about 1mm from the terminal. Adjust the terminals so that the core wire is not over- or under-crimped. Next, place the crimp site on the die. Make sure that the brazed part of the terminal is on the side of the on-die.


Operate the crimping tool and start crimping. For both manual and electric crimping tools that have  a shock mechanism to indicate that crimping is completed, repeat the operation or continue pulling the switch until you feel the shock.

For one-handed crimping tools, a forming confirmation mechanism is provided to open the handle when crimping is complete. Tighten the handle firmly until it opens. When crimping is completed, the terminal will be stamped with the standard of the dies used.

Precautions for use

Since crimping tools are used for electrical wiring, improper use may cause shorts or disconnections, and in severe cases may result in serious accidents such as fire. Please pay close attention to the following points when working with crimping tools.

Use appropriate tools

Do not force work that is outside the applicable range of the tool. For example, if a terminal with insulation coating or a closed-end junction is forcibly installed with a tool for bare crimp terminals, the insulation coating will be crushed or broken at the crimped part and the required withstand voltage will not be achieved.

Peel the insulation at an appropriate length

The length of wire insulation to be peeled depends on the terminal to be installed. Check the work instructions for the terminal and follow them carefully. If the peeled length is too long or too short, the performance of the crimp will be affected in both cases.

Be careful when installing crimp terminals

Even  with proper crimping using the appropriate tool, the crimp may fail due to incorrect installation of the crimp terminal itself. Common mistakes that tend to occur are: the size of the crimp terminal does not match the thickness of the core wire, the crimp terminal is installed in the opposite direction, or the core wire is not inserted properly.

Crimping with the appropriate tooth gap

Crimp using a tooth gap that matches the size of the crimp terminals. If the gap is too large or too small, it cannot be crimped properly. 

Pay attention to the crimp position

Crimping must be done in the proper position. Follow the work instructions for the terminal to ensure the proper position before starting work.

Be careful of electric shock

Since work with crimping tools involves handling electric wires, make sure that there is no electricity flowing through the wires. Do not crimp live wires. Also, avoid working in an environment where there are live wires around, as it is dangerous.

Be careful of injury

Dies and handles of crimping tools have narrow openings and may pinch fingers and other objects during operation. Extra caution is required. .


Crimping tools are commonly used when connecting terminals to wires. For proper crimping, various standards must be observed  and correct usage must be checked to prevent accidents and injuries.