Por que usar uma chave de torque?
Or how to get just the right amount of force
17 de Março de 2017
Not too loose, not too tight, just get it right!
Manufacturers specify the right tightening value for every fastener on a vehicle. This is for a reason: SAFETY, not only for the driver but also for the passengers, and anyone that will come across the vehicle. When a customer brings in his/her vehicle, it's the mechanic's responsibility to ensure a total compliance of the job done according to the manufacturers specifications. The best way to do so is to use a precision tool to finish and control the job.
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? If you don't bring enough torque when tightening a bolt, there is a risk for the bolt or nut to spontaneously unscrew down the road.
- Too tight: The danger of applying too much force 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. You can even go for a manual torque wrench or for a pneumatic torque wrench.
- Manual Torque Wrench: Manual, 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 (Stall Torque tool or Shut Off Nutrunner): This is the most advanced solution, more adapted to heavy vehicle maintenance or very 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 some 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. In general, it is also important to look at the ergonomics of tool, such as the tool weight or the grip comfort.