What is Torque Calibration and How it is Performed? Zenith Instruments

The most commonly used tool to achieve proper load on a fastener is a torque wrench. Studies and research show that torque wrenches need to be calibrated on purchase and also periodically. Torque calibration will not remain constant over the lifetime of the torque wrench.

Why Torque Calibration Matters?

In an assembly line, regardless of how good the assembly process is or highly skilled labour is, if the torque wrench is off calibration, optimum results cannot be achieved. Most torque wrenches undergo excessive damage due to prolonged usage, and small discrepancies in accuracy will set in. These will hamper the accuracy level which will create a ripple effect down the assembly line.

That is why torque calibration is critical to the assembly process. If you want the wrench to click on target 200 NM, you don’t want it being off as much as 50 -70 NM. Regular torque calibration is critical to achieving optimum and consistent results in the assembly process compliant with the quality standards.

Torque Calibration Standards

The International Organisation for Standardisation (ISO) has provided two torque calibration standards. At Zenith, we provide torque calibration for manual torque wrenches that comply with these two standards. They are devised as Type I (Indicating) and Type II (setting) torque tools. Each of these standards provides in-depth requirements and procedure to maintain the accuracy levels by calibrating as stipulated by the standard.

The accuracy of the manual torque wrenches gets off due to all the physical shocks like dropping, hitting or banging that cause damages. The most common accuracy level for manual torque wrenches is about 3 -5%. It is recommended to calibrate them every 6 months in compliance with the ISO 6789 standard. The standard also mandates an annual recalibration regardless of how much (or how little) it has been used.

Torque Calibration Equipment

Torque Testers are used to accurately calibrate torque wrenches in labs. They are quality control devices, which are used for torque calibration. These modern torque testers can measure torque in both clockwise and anti-clockwise direction with the ability to convert the torque into many different units. They have a 3 –mode operation of the peak, first peak, and track.

Torque tester includes the following components that help in torque calibration:

  • Transducer: an electronic device that converts torque into an electrical signal. Made of strain gauges in a Wheatstone bridge configuration, an amplifier is used to amplify its electrical signal.
  • Digital Display: To convert the electrical signal from the transducer and convert it into torque units, which will be displayed on a screen.
  • Joint Simulator: is used for testing torque tools during calibration. It is usually placed over the transducers. By using multiple springs, the joint simulator can replicate hard, medium and soft joints.

Torque Calibration Service Sydney, Melbourne and Australia-wide by Zenith Instruments.

We calibrate and service all types of Torque Equipment. Our calibration laboratory is capable of calibrating torque from 0 to 2000 Nm. We can service, repair and calibrate any make and model of torque wrench.

We also provide on-site service and pickup/delivery service: To find more please call on 02 9680 8765 or 03 9562 0373.

We calibrate, service and repair the following Instruments:

  • Torque Meter
  • Torque Wrench
  • Torque Driver
  • Digital Torque Wrench
  • Torque Sensor
  • Torque Transducer
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