An Ultimate Guide On How To Calibrate Your Torque Wrench

There are situations where we need to tighten and set our screws and bolts using the desired torque. In such conditions, a torque wrench always comes to our rescue. But, a torque wrench is only as useful as the accuracy and precision. So it is important to calibrate your torque wrench at constant intervals for maximum efficiency and accuracy.

Let’s find out how to calibrate torque wrench!


Calibrating your torque wrench is generally performed by professionals in their workplaces. It is important to check and calibrate your torque wrench in regular intervals.

Most national and international standards for checking the calibration of a torque wrench are one year or 5000 cycles or whichever comes first. Some of the tool manufacturers have even introduced torque checking machines and mechanisms that can make the job easier and less time-consuming.

Points To Be Considered When Calibrating Your Torque Wrench

  • The calibration should be done in controlled temperature and humidity and this has to be recorded during the calibration.
  • The uncertainty of measurement of the calibration device should not be greater that +/- 1. This means that the calibration device has to be more accurate than the torque wrench.
  • ​The torque wrench should be used in the horizontal or the vertical plane and held in the vertical plane. Calibrating the wrench in the horizontal direction is unacceptable as the weight of the wrench can cause an error in the reading.
  • ​The torque wrench should be operated before taking the reading. This helps in the re-lubrication of the moving surface and resettling of the moving components.
  • ​The load applied should be towards the center of the handle of the torque wrench or wherever is specified by the manufacturer.
  • ​The rate of increasing torque should be controlled. The rate of application affects the torque reading.
  • ​The readings have to be taken at certain points that are in the range of the torque wrench and there should be 5 readings at each point. For setting the torque wrench, the target point should be approached from the lower part of the scale.
  • Some torque wrenches have two direction mechanisms while others have one directional. It is easier to calibrate a one direction wrench than a two direction one.

What Will You Need To Follow This Tutorial?

Torque Wrench Calibration Devices

There are devices that allow you to calibrate your torque wrench. These are available in mechanical, electrical and hydraulic models and can be used to monitor the rise in torque. The range of use of such devices is limited, though. The standards that control the calibrations set the range of use of these devices at 2 per cent to 100 per cent in the best case scenario and 10 per cent to 100 per cent in most normal cases.

Torque Wrench

A torque wrench allows you to tighten a bolt or nut with the desired amount of torque.

Step By Step Guide To Calibrating Your Torque Wrench

As we have discussed earlier, calibrating your torque wrench is a hard and time-consuming affair which is to be done by a professional at set intervals. But here are 2 ways in which you can minimize the error and maximize the accuracy. Let's find out how to calibrate torque wrench.

Tutorial 1: Weight Calibration

In this way, first, mark the back of the torque wrench at the center of the drive. Then, mark the position where your hand will be holding while using the tool and find the distance between the two marks.

Using a bench vise, secure the square head of the torque wrench in such a way that no part of the torque wrench touches the vice. Next, proceed to move the handle to a horizontal position.

Align the torque valve of the wrench to the value of the distance between the marks multiplied by 20 pounds.

Then, dangle a 20-pound weight from the first and second mark you made. If you hear a click sound from the handle of the torque wrench, lift the dangling weight and move it towards the wrench head until you are sure that the clicking has stopped. Mark this point and repeat the step for improved accuracy.

Next, find and record the distance between the square head and the marking that you just made. To find the correct amount of torque, multiply the value with 20 pounds or 9. 07 kg.

Using the formula Ta= Ts X(D1/D2), where Ta is the torque applied, Ts is the torque setting D1 is the distance measured between the center and where you place your hand and D2 is the distance between the square head and the mark, calculate the torque applied. You should make sure that the math is correct and the torque wrench is adjusted accordingly.

Check the video below for clearly steps:

Tutorial 2: Fish Scale Method Of Calibration

​In this method of calibration, secure and attach the torque wrench with a vise. Attach a fish scale at a distance of one foot from the center of the drive.

​Find the weight of the pull of the fish scale for a specified wrench setting.

​Using a calculator, find the percentage of error in the reading.

​Repeat the first step again for a different wrench setting and find the consistency in the error rate. Apply this percentage of error to the scale on the torque wrench to improve your accuracy and precision when using the torque wrench.

Check the video below for clearly steps:

​Some points to keep in mind before calibrating your torque wrench

  • Lift the weight off the handle of the torque wrench when finding and checking the click spot to ensure its accuracy.
  • Always give your tool to a professional for calibration if you are doubtful of your abilities. Calibration can be a hard and time-consuming job, but the professionals have machines and equipment for the job that makes it easy.
  • The weight you are using should be exactly 20 pounds or 9.07 kg.

Wrapping Up

A torque wrench can have a large variety of applications. But a torque wrench is only useful and effective if it is accurate and calibrated. It is important to calibrate your tool at regular intervals for best results.

​I hope that this article would have helped you in learning more about calibrating your tool and taking care of it. If there are any more doubts or queries, contact us through the comment section and share with your friends and family to spread the knowledge.

Abigail Jones

Hi, I'm Abigail. I like spending time tearing my house apart and putting it together back again. Join me on home improvement tutorials, tips on my blog.

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