How to Use a Torque Wrench
Posted by Katy | Toolstop on 26th May 2021
This Toolstop guide gives you the complete lowdown on torque wrenches, what they're used for and how to use one
What is a Torque Wrench?
A torque wrench is a type of tightening tool designed to apply a specific amount of torque to fasteners such as nuts and bolts. They are typically used in the automotive, construction and indstrial trade. In this Toolstop guide, we'll give you the complete rundown on torque wrenches, their uses, and which is best and why.
If you are looking for a new torque wrench, Toolstop has an extensive range.
How Does a Torque Wrench Work?
Why do I need a torque wrench and not just a spanner?
Certain fasteners, such as those on a vehicle, require a specific tightening value for safety purposes. If you don't apply the correct amount of torque, these nuts and bolts can become loose. But if you apply too much torque, you can damage the threads. For applications where nuts and bolts need to be tight and secure, such as tire tightening, a torque wrench is the tool for the job.
The torque wrench prevents you from over tightening fasteners which can cause damage or under tightening them which would leave them loose.
Having the correct torque set is essential for improved safety and performance of equipment. Torque wrenches should not be used to loosen bolts, only to tighten.
Setting a Torque Wrench
Torque is a rotational force. It is measured in lb·ft (pound-foot), lb·in (pound inch), or N·m (newton meter). The torque wrench will have these different markings on each side. The most common is foot pounds (lb.ft).
Each vehicle has a different torque specification set by the manufacturer. This can be found in the vehicle's manual.
You can change the settings on your torque wrench in order to increase or reduce the torque. To do this, simply turn the handle clockwise for more torque or anti-clockwise to decrease it. (more on this later).
To show how much torque is being applied, the tool will generally have a scale or display screen depending on the model.
Torque wrenches come in many styles and sizes with different torque ranges. The most common size is a 1/2" square drive, but again this depends on the fastener and application.
How to Use a Torque Wrench
Step by Step
The first step you want to take in using and setting up your torque wrench is finding out the torque value. As mentioned above, this can be found in the user manual, or sometimes online. Make sure you are looking at the correct scale on your torque wrench as most give you lb·ft on one side and lb·ft or N.m on the other.
- Loosen the knob at the bottom of the torque wrench. This will allow the handle to twist back and forth
- If the required torque is 100 lb.ft, you want to rotate the handle until the '0' meets the 100 lb.ft line
- Tighten the lock nut back up once you have set your required torque to lock it in place. This step is very important
- Put your socket onto the torque wrench
- Place it over the lug nut
- Simply grip the handle and tighten
- When you hear a click, the required torque has been met
Points to remember when using and working with torque wrenches:
- Once you hear the click, don't tighten the nut any further. One extra click is all that’s needed for the fastener to be overtightened.
- Don't use your torque wrench to fully tighten the fastener. Instead, do most of the work with your ratchet and then finish off with your torque wrench to get it to the required torque.
- You may need to use an extension if the socket isnt deep enough
- Always handle your torque wrench with care. Store it in its supplied case when not in use. This prevents it from knocks and bumps which could affect its performance, accuracy and calibration.
- When you store your torque wrench, loosen it to the lowest setting. This helps it to stay in calibration much longer as there isn't as much force on the spring.
Calibrating a Torque Wrench
Before using a torque wrench, it is extremely important that it has been calibrated.
Torque wrenches should be calibrated regularly to ensure they keep providing accurate and reliable results. This should be done by a professional. There is no set timescale as to how often your wrench should be calibrated as it comes down to how often the tool is used, though the recommendation is once every year or every 5000 clicks.
Types of Torque Wrench
There are a variety of different torque wrenches available on the market. We have highlighted our 3 favourites and their uses below.
Click torque wrenches:
Click torque wrenches belong in almost any tool box. They have a spring-loaded lever which is adjusted by twisting the handle to the right setting and will make a clicking sound when the correct amount of torque is reached. When the required torque level is achieved, the lever breaks which creates the clicking sound.
Most click types are ratcheting and may be used for tightening or loosening. You only want to hear 1 click. Any more and you are over tightening. These torque wrenches can be purchased in various sizes and torque limits. They are great for use in hard to reach areas.
Digital torque wrenches:
Digital, or electronic torque wrenches work from an electric sensor so don't feature any moving parts. They sense how much twisting force is applied and tell the user via a digital display. Simply dial in the torque setting you need and it will either beep or a light will flash, or both, when the correct torque is reached.
Some digital torque wrenches may even include a memory stick to save readings.
Beam torque wrenches:
Beam torque wrenches are some of the easiest to use and are the most basic form of torque wrench. They are most typically used in exact tightness applications, particularly on vehicles. They feature 2 beams - The first is a lever used to apply the torque to the fastener being tightened and the second is only attached at one end of the wrench head and serves as the indicator beam.
Our top pick for torque wrench brand is Norbar. Shop the range at Toolstop.
You should now be familiar with torque wrenches, how to set them up and operate and which one you should opt for. Torque wrenches are an essential tool in many trades. Toolstop is your one stop shop for professional torque wrenches.
Check out Norbar's top 5 torque wrench tips in our exclusive Toolstop video: