Selecting the Right Coupling

Choosing a coupling and coupling bolt for any application requires checking several factors: design, size, maintenance, and cost. There are many different kinds of couplings, but not all will fit your area of concern. 

Before you visit your nearest auto parts manufacturer in Australia, here are some tips to make your decision a little easier.

Torque Rating

The torque rating is a major factor in selecting a coupling. Torque rating refers to the amount of torque the coupling can transmit. 

It is important to know the transmission capability of a coupling to prevent it from sustaining damage. An underrated torque for the application may break the coupling, while an excessive rating may be stiff and bulky. Remember that the higher the torque rating, the less flexible and larger the coupling will be. 

Some examples of couplings with a high torque rating include gear, grid, and disc couplings. Meanwhile, elastomeric units offer lower torque.

Service Factor

After determining the torque rating, you should check the service factor (SF). The service factor accommodates fluctuations in torque for your application. Usually, engineers would apply an SF higher than 1.0, which pertains to the severity of the service.

But the problem is that manufacturers disagree with engineers’ values and instead would abide by SF values they developed. Depending on the material, the coupling SF values may change. To ensure you get the coupling with the ideal SF, look for one that is field-proven and recommended by engineers and manufacturers.


The material of your coupling will depend on how corrosive or damaging the environment might be. Titanium and MP35N are perfect for highly corrosive environments, while stainless steel suits medical settings. 

Additionally, you should consider the temperature. Elastomeric couplings may not do well in high temperatures, but Inconel is better since it won’t easily lose integrity.


In the event of an element failure, a fail-safe coupling can continue to transmit power. One example of a fail-safe coupling you might want to get is a jaw coupling. Meanwhile, some alternatives are not fail-safe and will stop sending power when the element fails.

High-Quality Couplings for your Application

Another factor when choosing couplings is the quality offered by the manufacturer. Poly Flex couplings are molded from engineering heat-cured polymer alloys of the highest standards. Visit their website Contact us to learn more.