How to Read a Torque Tool: A Quick Guide
What is torque and why is it important?
To start with, torque is the amount of rotational force used to fasten a bolt and nut together, and it plays a critical role in the integrity of things like bridges, flanges, wind turbines, and other industrial structures. It is typically measured in foot pounds (ft.-lbs.) or Newton-meters (Nm).
Correct torque matters since improper tightening is dangerous. Both over and under-tightened bolts can lead to catastrophic failure, like what happened at the Lemnhult wind farm in Sweden in 2015.
What Is a Torque Wrench?
An industrial torque wrench is a precision instrument designed to apply a specific amount of rotational force, or torque, to a fastener. There are different kinds of torque wrenches.
- Hydraulic Torque Wrenches are powered by a hydraulic pump. They can generate an immense amount of torque, making them ideal for tightening the large bolts found on bridges, buildings, and pipelines.
- Pneumatic Torque Wrenches (also known as air-powered wrenches) use compressed air to deliver high torque. Their high efficiency and ergonomic design also help reduce operator fatigue.
- Electric Torque Wrenches are usually battery-powered and have digital displays and controls. Many modern electric torque tools can record torque values for each bolt, providing a verifiable record for each bolting job.
- Manual Torque Multipliers use a system of internal gears to multiply the force that occurs when an operator moves it, allowing them to tighten very large fasteners without the need for a power source.
How to Read a Torque Wrench
- For a hydraulic torque wrench, check the required torque and use the accompanying torque chart to set the pump pressure. Watch the gauge and stop the pump when the needle reaches the correct amount.
- With a pneumatic torque wrench, find your model’s torque chart, adjust the air regulator, and confirm the pressure on the gauge. Pull the trigger until the tool stops or signals the correct torque.
- For an electric torque wrench, power on, select the torque in ft-lb or Nm, and confirm on the display. Pull the trigger until the tool stops or alerts you. The torque measurement will show on the tool's screen.
- With a manual torque wrench, unlock the handle, set it to the desired torque, and lock it again. Pull steadily until you hear the click or see the pointer reach the mark.
Common Mistakes
When working with torque tools, a few common mistakes can cost time and safety. One of the biggest errors is misreading the display. For example, confusing units like foot-pounds and Newton-meters can lead to applying the wrong amount of torque. Always double-check which unit your tool uses before setting or reading torque values.
Another mistake is skipping regular calibration. Over time, torque tools can lose accuracy. Make sure to schedule calibration checks according to the manufacturer’s specifications to keep your tools reliable and your work precise.
Also, for pneumatic and hydraulic tools, improper pressure settings are common issues. Using the wrong air or pump pressure will cause inaccurate torque readings, so always follow the manufacturer’s torque-to-pressure charts carefully.
Take a moment before starting your job to verify settings, confirm units, and inspect your tool’s calibration status. This simple routine prevents costly errors and keeps your projects on track.
Get the Right Bolting Tools with HYTORC
With over 55 years of experience, we're focused on innovative, high-quality, and safe industrial bolting tools, pumps, and washers. We're committed to making industrial bolting simpler, safer, and smarter. Our mission is to optimize safety, quality, and schedule in industrial bolting through innovative solutions and an unyielding commitment to world-class customer service. When you're ready to explore how a superior industrial torque wrench can improve your operations, we're here to help.
