TALKING TORQUE: The 5 (somewhat surprising) reasons your torque wrench may not be accurate & what you can do about it

Joshua calibrating a torque wrench

Sorry to be bearer of bad news, but there’s a very real chance your torque wrench isn’t quite accurate.

And if you use a torque wrench in your business, it’s critical to know that your fastener is tightened to a specific torque value. Otherwise, why bother with a torque wrench in the first place, right?

Here are 5 somewhat surprising reasons why your torque wrench may not be as accurate as you think, and how to fix it.

1. Accuracy wanes

Here’s the harsh reality: While the accuracy of your torque wrench is specified by the manufacturer, you simply cannot be certain that it’s providing consistent, accurate results unless you validate its performance… regularly.


You see, torque wrench accuracy specifications can range from 6% – 1%. And while premium torque wrench brands may retain their accuracy for longer, even higher quality brands can produce inaccurate results over time. Which means it’s critical to calibrate the tool often enough to trust its performance. And when using less expensive brands made from lower quality parts, even more frequent calibration is necessary to ensure you’re getting the right results and complying with relevant industry standards.

2) Usage matters

This may sound obvious but it’s important to emphasise because it’s easy to get this wrong: The more often you use your torque wrench, the more often it will need to be re-calibrated to ensure accurate performance.h

In case you haven’t visited the official website of the International Organization of Standardization lately, ISO 6789 clarifies the absolute minimum standard: a torque wrench should be re-calibrated every 5000 uses or every 12 months. Yet, if your accuracy requirements are high, don’t just rely on that bare-minimum baseline. Industry experts suggest re-calibrating your torque wrench every 2500 to 3000 uses.

How many uses has it been since you last calibrated your tool?

3) Storage issues

How do you store your torque wrench? Do you store it at its lowest marked setting?

Here’s the bad news: If you store it at a torque value higher than its lowest setting (usually 20% of max.), the tension spring remains under an increased load and will weaken over time, causing your torque wrench to produce less torque across the range and reducing its accuracy. And, by the way, if your torque wrench is set back to zero, various components in the tool can move slightly, again affecting its accuracy.

So if you’ve been storing your torque wrench in either of these ways over a long period of time, it may not be delivering the accuracy you require.

4) Check the Weather

Do you ever use your torque wrench in extreme temperatures (below freezing or very high)? Do you ever use it (or leave it out in) the rain?

Well, these actions can result in premature rusting. And when the internal mechanisms of your torque wrench rust, its accuracy and performance is affected.

5) Use it Wisely

Be honest. Have you dropped your torque wrench recently?

Believe it or not, dropping your wrench even once can reduce its accuracy by 30%!

Have you used your torque wrench as a breaker bar or in any other non-standard way?

Well, torque wrenches are designed to be used by applying the right amount of pressure to its grip. Using your wrench in any other way can overload it and affect its accuracy. In fact, ISO-6789 mandates that any torque wrench that has been overloaded by more than 25% must be re-calibrated.

What should you do?

It goes without saying that at a minimum you need to have your torque wrench calibrated (by accredited experts) as per the standards relevant to your industry.

But if you believe that any of the above factors may affect the accuracy of your torque wrench – even if it’s within the specified re-calibration timeframe – don’t risk it. Get it re-calibrated.

And if you need help, speak to our accredited, australia-wide calibration team about our drop off and delivery service to get your equipment back into working order fast.

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