What is a Compression Crimp?

A compression crimp is am efficient method of joining or terminating cables or wires. The term refers to the process of restricting or compressing a lug or ferrule tightly around a wire to form a secure mechanical or electrical union. A compression crimp is typically carried out with a hand or hydraulically powered tool fitted with specially designed jaws which compress the ferrule or lug to facilitate the crimp. This type of crimping tool generally imparts an oval or hexagonal restriction on the body of the connector which, if the connector size is correct, forms a high strength join or termination. A compression crimper does not impinge or force any part of the connector into itself as is the case with a stab crimp making it ideal for use on hard, single core wires.

A compression crimp is a quick and cost effective way of achieving a good connection. Compression crimpers are typically tools which resemble a pair of pliers with jaws equipped with either one or multiple crimp points. These crimp points are typically located with one half on each jaw of the tool. When closed, the two halves form an oval or hexagonal opening. These crimp points are generally numbered or have the intended ferrule or lug size marked on them to indicate the correct termination to use. These crimp points are smaller than the connectors they are intended for; when such a connector is placed in the opening and crimped, the tool compresses the body of the connector tightly onto the wire.

Crimping tools range in size from small, pocket sized hand tools to hydraulic machines capable of crimping the largest, high-tension cable joints. Hand operated examples may have articulated jaw systems which give more mechanical advantage when crimping larger connections. Hydraulic crimpers may be connected to an external hydraulic source or fitted with an integral, hand pump system to complete the crimps. These machines usually have a clam shell type head which accepts several different dies for various connector sizes.

A wide range of ferrules for joining cables and lugs for cable termination are available which are suitable for compression crimp applications. These are generally made of copper for electrical connections and aluminum or steel for mechanical joints. Mechanical compression crimps are usually used on small, light load applications such as stranded steel fishing traces and non-load bearing steel ropes. A compression crimp is better suited for single strand electric wires than a stab crimp; it does not press a portion of the ferrule into the wire which tends to weaken the copper core, often causing it to break.