In industries where safety and reliability are crucial, such as automotive, aerospace and manufacturing, ensuring the integrity of every joint is essential. Bolts and other fasteners must be tightened to the correct torque level to ensure safety and reliability.
Torque refers to the rotational force applied to an object, and the amount of torque used directly affects how securely the bolt is tightened. A vital aspect of torque measurement is understanding the different types of joints and when to use them.
We’ve previously explored what a soft joint is [www.crane-electronics.com/what-is-a-soft-joint]. Now it’s time to look at hard joints and their applications.
What is a hard joint?
It’s important to understand that not all joints are the same when it comes to torque measurement. Some joints are more rigid than others, and these are commonly known as hard joints. They are frequently used in manufacturing and engineering to help ensure the precision of the connection and improve the performance and safety of the assembly.
Hard joints, typically used in assemblies with strong materials like steel and aluminium (e.g. metal to metal contact), provide a high level of precision. These rigid metals offer resistance, allowing the fastener to secure the joint to the correct torque with minimal rotation, ensuring precise and accurate results.
When using hard joints, it’s imperative that the application of torque is carefully controlled. The torque level can rise quickly as the fastener engages, which can lead to overtightening. Overtightening can damage the fastener and the threads or even lead to cracking in the materials being connected, compromising the safety and reliability of the entire system.
Incorrect torque applied to hard joints may result in mechanical failure, and this affects the whole system since its safety and reliability will be reduced. That is why it’s vital that the right torque measurement tools must be used.
How do hard joints work?
Now that we have covered what a hard joint is, let us take a closer look at how they work. Here is a breakdown of how a hard joint functions:
- Compression: When a fastener, say a bolt, is tightened, the components hardly deform/compress, resulting in almost an instantaneous increase in resistance (friction) when the fastener engages.
- Applying torque: Due to the rigidity of the materials, the torque increases quickly with hardly any turning of the torque wrench or tool.
- Short tightening angle: With the instant resistance developed from the materials, there is little, if any ‘give’ when tightening a fastener so overtightening can easily happen. Correct torque measurement tools will help in controlling and applying the appropriate torque. For example, Crane’s wrenches offer a series of features like vibration, audible alerts and red/amber/green status light rings, designed to stop the operator from over torquing, unlike typical mechanical wrenches.
When are hard joints used?
Hard joints are used when reliability, performance, durability and precision are non-negotiable. They are often used for joints and connections that are subject to high stress and high impact, such as:
Automotive
- Engine components: Hard joints are used to secure parts such as cylinder heads, engine blocks and transmissions.
- Suspension systems: Hard joints are frequently used to attach control arms, struts and other load-bearing parts.
- Braking systems: Hard joints are used in brake assemblies to ensure reliability and performance.
Aerospace
- Aircraft: Strength is a crucial factor in assembling an aircraft. Hard joints are used to attach the airframe, wings and other structural components.
- Landing gear: Aircraft landing gear encounters high stress and impact, hard joints are used in the assembly of landing gear to secure components.
- Engine mounts: Hard joints in the engine mounts help them withstand extreme conditions and vibrations.
Manufacturing
- Assembly lines: Hard joints help improve reliable connections for consistent production in machines and robotics.
- Heavy machinery: Industrial presses, conveyor systems and other equipment that handle heavy loads all use hard joints.
Construction
- Steel structure: Such as steel beams, girders and other load-bearing structures use hard joints to enhance stability and safety.
- Cranes: Hard joints are used in heavy lifting machinery to ensure they can support large weights safely and without failure.
Other applications
- Electronics: Hard joints are used in sensitive devices to help reduce movement and vibrations that could damage the devices.
- Marine: Hard joints are common in shipbuilding. They fasten joints in the hull sections to help them withstand harsh marine conditions and environments.
The benefits of hard joints
Hard joints are known for their durability and strength and are used in applications that must withstand considerable force and loads. Their rigidity ensures long-lasting connections with little risk of loosening in harsh conditions where vibrations, high temperatures and heavy loads are common. Hard joints also allow for precision and accuracy in torque measurement.
Hard joints, in addition to their durability and reliability, require less maintenance. Their strength and resistance to loosening mean they can last longer without the need for inspection, adjustments, or repairs. This not only reduces downtime but also helps lower maintenance costs, making them a popular choice in the automotive and aerospace industries.
Overall, hard joints provide robust, precise, and reliable connections that are essential in many high-demand applications. Their strength, stability and resistance to loosening make them a preferred choice across industries where safety and performance are critical. Hard joints can also help contribute to a safer working environment by reducing the risk of accidents and injuries on the assembly line.
Crane Electronics, experts in torque management
With more than 50 years of experience improving quality, maintaining accuracy and maximising reliability in manufacturing environments, Crane Electronics is a global leader in torque engineering.
We are committed to improving the quality, safety and efficiency across manufacturing industries worldwide by providing bespoke torque management solutions, including various high-precision torque wrenches.
Our products and services offer complete traceability and help increase productivity, ensuring our customers can achieve consistently accurate results and mitigate the risks of torque relaxation.
For more information about our ranges of torque measurement solutions or for any assistance with our products and services, please contact Crane Electronics on 01455 25 14 88 or email sales@crane-electronics.com.