What is a Torque Wrench?

A torque wrench is a tool that is used to control and apply a specific torque to a fastener, such as a bolt or a nut. Understanding the benefits to your assembly process and making sure that you’re using the right tools can provide an increase in productivity and accuracy. Here are a few basics to remember:

1. A torque wrench is a precision tightening tool, so only use it to tighten, never to loosen.
2. Any shock to the tool can affect its calibration, so be sure to handle your torque wrench carefully and store it in its box when not in use.
3. The torque wrench should be reset to the lowest value anytime it is not in use or at the end of each day so that the string pressure is released.
4. Only use one hand to operate the wrench, and use fluent and continuous movement. Most torque wrenches have a mark on the handle to show you where to apply pressure.
5. As tempting as it is, do not use an extension on the handle. The wrench will not give you a true signal.
6. A torque wrench helps to avoid over-tightening, but they are not foolproof. When the set torque is reached, the operator will hear a clear click sound. If the tool clicks while stationary, it means that the application has already been over-tightened. In this instance, it’s best to start over – loosen the bolt first, tighten with an adapted tool and finish with the torque wrench to reach the correct and safe torque.
7. Since it is a high precision tool, a torque wrench needs to be re-calibrated on a regular basis. We recommend a tool re-calibration each year or every 5000 cycles, whichever comes first. Also the servicing should be done at an official service center.

What are the risks not using a torque wrench?

Too loose: Have you ever paid attention to all those wheels you can see by the roadside? They likely came loose because someone didn’t tighten them down properly. The same goes for assembly: if you apply torque properly there is a risk for the bolt or nut to spontaneously coming undone creating a safety and compliance issue.

Too tight: The /the-importance-of-proper-torque/ is mainly to compress, bend or strongly damage both of the parts that are bolted-together. At one point, the bolt shank will break and all the parts that should remain would fall apart.

How to choose the right torque wrench?

You can find different types of torque wrenches on the market. Which type you go for depends on factors such as the application, need, and price point. Getting the one that is exactly right for you may require a custom tailored solution.

Manual Torque Wrench: Hand operated and easy to use, this type of tool is most commonly used in the light vehicle maintenance industry, and covers the essential of the applications.

Pneumatic Torque Wrench: This is a more advanced solution for more adapted high load applications such as truck wheel tire change or construction machine maintenance. Since the price of this type of torque wrench is higher than a manual one, you would be considering this solution for applications requiring 516 ft.lbs/700 Nm and above.

What to look for in a torque wrench?

When it comes to choosing a torque wrench, manual or pneumatic, the most important factors will be the quality & accuracy of the tool itself. Here are two final pieces of advice to guide your choice:

Manual Torque Wrench: A good thing to check first when choosing a manual torque wrench is that the tool is actually fitting the norm ISO 6789: 2003, ensuring the tool calibration complies with the best set up. Each torque wrench should come with a calibration certificate.

Pneumatic Torque Wrench: When it comes to pneumatic torque wrenches, it is important to check the quality and durability of the material used, with a specific look at the reaction bar for shut off tools. You can consider that the tool has good performances when it offers a >8000 cycles before maintenance. With these tools, it’s important to consider safety, so look at the ergonomics of tool such as the tool weight or the grip comfort.

Martin offers our customers the expertise to make sure that they choose the right product for their application and that they are used properly. Click here to learn more about Martin, or contact us to get a consultation setup today!