Swaging and Crimping
The terms Swaging and Crimping are often used interchangeably which can be useful but may be very misleading. Swaging is a process ‘very’ close to crimping but is differs in meaningful ways and use different types of machines. In swaging, a machine compresses or pushes a fitting and ferrule through a fixed split die bed to reduce the OD of the ferrule to pre-determined and well-specified dimensions yielding a predictable and reliable ‘strength of connection’. In comparison, a crimping machine has a number of narrow dies that close around the ferrule or sleeve and reducing it to a predetermined OD by taking ‘bites’ into the fitting.
Overview
Crimping secures components by deforming a metal sleeve around them, creating a strong bond without altering the components’ fundamental shape. Crimping can be characterized as creating an “interference fit” and is generally achieved by applying the process to smaller dimension components with manual tools. With wire rope – the sleeves intended to be crimped are typically Hourglass (Duplex) or Round (Simplex)
Swaging, in contrast, uses compressive force to deform the fitting itself onto a hose or wire rope, physically bonding the two parts together and reducing the diameter of a tube or fitting. Swaging generally provides a more permanent and stronger connection, often used for high-pressure or high-tension applications like hydraulic lines and architectural cable. With wire rope – the sleeves intended to be swaged are typically Oval (Duplex) or Round (Simplex)
Process Details
Crimping
- Method:
- Compresses a separate metal sleeve or ferrule around two components, like a hose and a fitting, or electrical wires and a connector.
- Effect:
- The ferrule is deformed and shrunk to secure the components, but the original shape of the components themselves is generally maintained.
- Application:
- Primarily used for joining electrical wires, network cables, and for securing fittings onto hoses for less demanding applications.
- Bonding Strength:
- The connection relies on the physical compression of the sleeve around the parts.
Swaging
- Method:
- The fitting itself is compressed and shaped around a hose or wire, creating a permanent physical bond by reducing the diameter.
- Effect:
- The material of the fitting is permanently deformed and shaped to hold the inner component securely.
- Application:
- Used for strong, high-tension connections such as hydraulic lines, exhaust systems, and architectural wire balustrades.
- Bonding Strength:
- The fitting and the component become physically bonded, with the outer material deformed around the inner one.
Application to Wire Rope
Swaging of wire rope was ‘invented’ by the Talurit Group in 1948 as a replacement for physically splicing wire rope. The process is carried out on ‘fittings’ that are used to terminate an end of wire rope. Swage Sleeves are generally used to terminate wire by forming either
- loops (properly termed a Soft Eye or a Hard Eye),
- splices (overlapped wires form a Lap Splice) or
- stops that terminate wire rope with a stopper at the end of a line, anchoring the line and preventing its end from passing through other materials.
In all cases, the intent is to allow the wire to attached to something else in a useful and predictably strong manner. With respect to wire rope, swaging with terminals or fittings is actually a cold forging process.
However, there are a LOT of different types of terminals, swage sleeves, crimps, and ferrules. A full discussion of all types is relevant to Riggers and is beyond the scope of this article. Elsewhere, our article on Swaging a Stainless Steel Terminal deals with Stainless Steel fittings. And a related article deals with Swaging Tools. The remainder of this article provides an overview of Swage Sleeves.
What Are Wire Rope Crimps, Swage Sleeves or Cable Ferrules?
A Swage Sleeves are generally a superior and recommended alternative to Wire Rope Grips. There are three major categories of swage sleeves based on their shape, purpose/performance, and material. There are complementary articles that deal with: