Why Are Crimp Dimensions So Important?

When it comes to hydraulic hose assembly, one of the most important checks is also one of the easiest to overlook: checking the finished crimp diameter. 

The correct crimp dimension ensures that the fitting has been compressed onto the hose to the specification set by the hose and fitting manufacturer. Too loose, and the fitting may not have enough grip on the hose, increasing the risk of leakage or the fitting pulling off under pressure. Too tight, and you can potentially damage the hose reinforcement or fitting, reducing the life and integrity of the assembly. 

An incorrect crimp dimension can also present itself in ways that make it appear as though the hose itself is at fault. For example, over crimping can cause internal damage to the hose reinforcement or tube. This damage may not be immediately visible but can later result in failures such as pinhole leaks. These don’t necessarily develop around the crimp, further obscuring the potential issue. 

This is why checking crimp dimensions is also an important part of failure analysis. Before assuming a hose failure is due to a manufacturing or product defect, the crimp dimension should be checked to help determine whether the assembly process may have contributed to the failure. 

In my experience in the hydraulics industry, I see a lot of people relying entirely on the crimping machine being correctly calibrated. The thinking is often, “The crimper is set correctly, so the hose must be right.” 

But calibration isn’t the same thing as verification. 

Crimpers are mechanical machines. Dies wear, components move, settings can change, and different hose and fitting combinations can produce different results. Even a well-maintained and calibrated machine doesn’t remove the need to physically check the finished crimp. 

A quick measurement with vernier calipers takes very little time and confirms that the assembly you’ve just made meets the manufacturer’s specified crimp diameter. 

It is also important from a warranty perspective. If a hose assembly fails, one of the first things that may need to be established is whether the hose was assembled to the manufacturer’s specifications. Being able to demonstrate that the correct crimp dimension was achieved is a huge part of this. 

Without that verification, supporting a warranty claim can become much more difficult. It can also make it difficult to determine whether a failure was caused by the hose, fitting, application, or the assembly process itself. 

At Taipan, we believe crimp dimensions should be treated as a critical part of the hose assembly process, not just a number on a crimp chart. 

Taking a few seconds to measure and verify the finished crimp can help prevent failures, improve traceability, support warranty claims and, most importantly, ensure the hose assembly has been manufactured correctly and safely. 

View or Download our Crimp Chart: