Torque wrench maintenance and testing
Find out about different types of power tools for torque application and their maintenance techniques


Fastening tools are indispensable for any key assembly operation. Imagine a high volume automotive plant. If a vehicle has 1000 threaded fasteners and the plant assembles 300,000 vehicles every year, that means there are 300 million run-downs performed every year in that assembly.

To smoothly run that kind of operation, fastening tools require regular maintenance and calibration. Depending on the type of tool and the volume of work it performs, torque tools require different types of maintenance and testing.

Additionally, regular oiling, cleaning, and replacement of worn-out parts have to be scheduled.

Types of Power Tools

Depending on the structure and mechanism, Power Tools which are used to tighten the fasteners, can be categorized into two broad types:

  1. Pneumatic Tools
  2. Pulse Tools

1. Pneumatic Tools

Pneumatic tools require relatively little maintenance. When they need to be fixed, the repairs are simpler and less costly. These tools are powered by the compressed air running through an air motor. The force of the air turns the driveshaft, and that rotary motion turns the fastener. To keep your pneumatic tool in good shape, you must ensure that they are supplied with clean, dry and lubricated air.

Once a week, the engineers should check the condition of hoses, power cables and connectors. After regular intervals, it is important to lubricate the gear head. It is also important to inspect tool suspension components, torque reaction devices, and FRL units.

Replacement of worn-out parts should also be performed after regular intervals.


2. Pulse Tools

Pulse tools enhance productivity by applying torque with precision. They apply torque in small increments rather than in one continuous blow. Using a pulse tool like a torque wrench ensures quality and precision.

Pulse tools use the hydraulic mechanism which consists of two rotating cylindrical parts. One of the greatest advantages of a pulse tool is that the hydraulic fluid absorbs most of the vibration from the fastening process. Consequently, the vibration is reduced and torque reaction can easily be controlled.

Pulse tools are more frequently required in the production and assembly of heavy equipment like power plant machinery, oil and gas assets, as well as aerial, naval, and terrestrial vehicles where the fasteners are required to bear a significant amount of stress.

In such industries, it is important to tighten the fasteners with precise torque. Pulse tools not only provide accurate torque but also absorb all the shock and smoothly tighten the fasteners.

Tool calibration is of key importance to ensure accuracy in torque application. To optimize the performance of a pulse tool, regular torque testing is of importance. With the help of a torque tester or a torque sensor, the output of a pulse tool can be adjusted.

Testing and Calibration

Regular testing and calibration ensure that your torque equipment is in good condition. Calibrating or maintaining a torque tool ensures repeatable accuracy and adherence to international standards.

Torque Sensor

Torque Sensor or a torque transducer measures the torque on a rotating system like an engine, a rotor or a bicycle crank. Most of the torque sensors achieve this by conditioning the shaft with permanent magnetic domains. Ideally, it is used for calibrating hand screwdrivers, wrenches or power tools performing a similar function.

Digital Torque Tester

Digital torque tester allows you to measure the health of your torque wrenches and other torque equipment with ease. It can easily be mounted on a wall or placed on the floor to conveniently test torque wrenches or other torque screwdrivers. Most of the digital torque testers have a touch-pad screen which captures peak torque values during the test and requires an AC/DC power supply.

Key Takeaway

The fasteners can be tightened with the help of a variety of power tools. Broadly, such torque power tools can be categorized into two main types i.e. Pneumatic and Pulse Tools. The two types of torque tools operate through different mechanisms and have different usage.

Depending on the nature and volume of the tasks performed, each torque power tool requires a different kind of maintenance and calibration. Most of the Pulse tools are tested and calibrated with the help of equipment like torque sensors and testers.