In industries where precision and reliability are crucial, torque checking is vital to ensuring the safety, performance and durability of fasteners, bolts and nuts during the tightening process. Whether it’s in automotive, aerospace, rail, solar and energy or heavy industry engineering, verifying the correct application of torque is critical.
With more than 50 years of experience, creating high-quality torque measurement solutions, Crane Electronics stands at the forefront of providing the tools and technologies that make this possible.
In this article, we take a look at everything you need to know about torque checking, the torque checking methods that are commonly used, the different tools used for the validation of torque and everything else in between.
Why is torque crucial?
Many manufacturing environments and industries depend on torque measurement to ensure every bolt and fastener is tightened to the exact correct measurement. When it comes to torque, there is no margin for error.
Under-tightening components can cause them to become loose over time, leading to breakdowns or even failures. Over-tightening fasteners can damage the materials, strip threads and compromise performance.
Whatever the application, if you’re assembling cars, maintaining wind turbines or validating assembly line tools, adopting robust torque checking practices ensures compliance, safety and reliability.
Where is torque checking applied?
Wherever torque specifications are used to securely fasten components, torque checking should also be used to ensure the torque applied is accurate and compliant. These are just some of the industries that incorporate torque validation in their assembly and quality control applications:
- Automotive
- Aerospace
- Construction and Heavy Industry Equipment
- Medical Devices
- General Manufacturing e.g. electronics, white goods etc.
- Rail, Subway and Rapid Transit
- Renewable Energy e.g. Solar, Wind & Hydropower
Torque checking is an essential part of torque measurement as it delivers peace of mind and confidence that the correct torque levels are applied and the high costs of downtime and product failure are avoided.
What are the different methods of torque checking?
When it comes to torque checking, there is no one-size-fits-all. The method you use will depend on the size and type of fastener and the role it plays in the overall performance and safety of the product.
Understanding the process and benefits of the most common torque validation methods will help you make a more informed decision about which is best for your application. The different torque checking methods are explained in more detail below.
Point-of-Assembly (process capability)
This is the process of measuring torque during the assembly process, as fasteners are being secured to the assembly. Torque checking and measurement tools allow manufacturers to apply and verify the correct application of torque during the assembly of products, vehicles or components. This can be done by using rotary torque transducers between the fastener and the power tool applying the torque. Data collectors can analyse the torque being measured by the transducer.
Post-Assembly Audits (process verification)
Possibly the most common torque checking method, post-assembly audits involve checking the torque applied to fasteners after the product has been assembled. These types of torque validation audits are often carried out with a digital torque wrench to confirm the right level of torque has been applied.
This type of torque checking method is quick and easy to perform, making it one of the most popular procedures for torque checking. However, care must be taken to avoid disturbing the joint unnecessarily during the audit.
First Movement or Breakaway Torque
The breakaway torque checking method measures the amount of torque needed to initiate movement in a tightened fastener. It is mainly used in applications where vibrations, temperature change and material setting can potentially cause torque loss.
By measuring the first movement, engineers can determine if there’s sufficient residual torque in the fastener for a safe and effective joint or if it needs re-torquing without having to disassemble the joint.
Marking Methods
The marking method is a simple torque checking method that applies a small paint or ink mark on the head of a bolt and the surface it’s mounted to. During inspections, technicians can clearly see if there has been any movement and therefore loosening of the bolt, which would indicate torque loss.
While this method doesn’t specifically measure torque, it does provide a clear visual cue that the torque levels may have changed and need verifying. This is a common torque checking method for environments where visual inspections are part of routine maintenance, such as construction.
Direct Tension Measurement
Possibly the most accurate, yet most complex torque checking method, direct tension measurement measures the tension in the fastener to give a precise indication of the clamping force applied.
Strain gauges can be used as part of this torque validation method to measure how much a bolt stretches when tightened. Often reserved for high-risk and critical applications due to the specialised equipment and knowledge required, direct tension measurement is a torque validation method that’s usually used in aerospace and nuclear industries.
Best torque checking tools
The types of tools used for torque checking can vary from simple handheld tools to more complex measuring systems. Some of the most common torque checking tools include:
- Digital Torque Wrenches
- Torque Testers and Analysers
- Sensors and Transducers
- Torque Data Collectors
- Dial and Click-type Torque Wrenches
- Torque Screwdrivers
- Strain Gauges
With increasing importance on compliance, automation and traceability, more and more modern production lines are using digital and sensor-driven tools for their precision and data recording abilities.
How calibration helps with torque checking
Even the best torque tools can and will lose accuracy over time, which is why regular calibration is essential and recommended under the industry standards ISO 6789. Keeping a detailed record of calibration also helps with traceability, which can prove invaluable during audits or demonstrating compliance.
Proper torque checking ensures safety, compliance and reliability across many industries. By understanding and applying the right methods with the right tools (as well as calibrating them regularly), you can avoid costly downtime and ensure long-term performance. To find out more about calibration, read our article ‘Three signs your torque equipment requires calibration’.
Why choose Crane for torque checking tools and calibration?
Whether you need digital torque wrenches, torque testers, sensors and transducers, we have a wide range of torque equipment available for torque measurement and tool auditing applications.
Browse our full product range, and if you need any additional support or would like to speak to one of our experts, please do not hesitate to contact us.
At Crane, we also offer technical advice, high-quality support and dedicated UKAS-accredited or NIST-traceable torque calibration services from our certified calibration centres. If your Crane torque equipment is due to be calibrated, explore our calibration services and book your tool in.