When it comes to precision engineering, accuracy is vital. Regardless of the industry, ensuring that bolts and fasteners are tightened to the correct levels is imperative for optimal performance, safety and long-term reliability. While torque is the go-to measure for tightening bolts, it doesn’t always give you the full picture.
This is where angle comes in. By measuring both torque and angle, engineers can gain a clearer view of what’s happening inside a joint. Combining these and measuring torque alongside angle delivers greater consistency and better control.
In this article, we take a closer look at what angle is in the context of measurements, why it’s so important and how it’s measured in both digital torque wrenches and rotary transducers.
What is ‘angle’ in fastening?
When we talk about angle in fastening, we’re referring to how far a bolt turns after it’s been tightened into position. This is measured by the number of degrees it rotates beyond a certain point. The starting point is often referred to as snug torque, which occurs when the bolt has made contact with the surface and cannot be tightened any further by hand.
From this point is where angle is measured. If the bolt is tightened another quarter turn, that’s roughly 90 degrees of angle. If it does another half turn, then that would be 180 degrees of angle. Understanding and recording the angle can help determine how much the bolt is being stretched and how tightly the joint is clamped.
Unlike torque, angle isn’t influenced by things such as friction or lubrication. This is one of the main reasons why torque and angle should be measured together to ensure accuracy, precision and reliability.
Why are torque and angle used together?
Torque measurement is the gold standard for measurement accuracy. Torque tells engineers how much rotational force is being applied, preventing over- or under-tightening of bolts and fasteners. This helps engineers determine the tightness of a joint, ensuring reliability and safety.
Precision, better control, fewer errors and greater consistency can be achieved when torque and angle measurements are combined. Torque is used to get the bolt securely into position, and then the angle is measured to give a more reliable fastening process. Taking this approach can help ensure the correct tension is achieved, not just the right resistance.
Some of the most common applications for using torque and angle measurements together include:
- Cylinder head bolts in engines
- Structural joints in aerospace
- Load-bearing assemblies in industrial machinery
Taking this two-pronged approach can also be useful in detecting any issues, such as cross-threading or worn threads. These issues can be highlighted when the correct torque is applied, but you do not reach the expected angle. Using both measurements together gives engineers confidence that they are achieving the right clamp load every time, giving them peace of mind when it comes to safety and quality.
How is angle measured?
Two of the most common ways angle is measured with torque include using:
- Rotary torque transducers
- Digital torque wrenches
Both methods and tools can measure how many degrees a fastener turns after the known starting point. The best method for your application will depend on whether the job is manual or automated and how precise the process needs to be.
Measuring angle with Rotary Torque Transducers
In environments that rely on automated or high-volume applications, rotary torque transducers are often the best tool for measuring angle. They’re positioned between the power tool and the fastener to measure both torque and angle simultaneously.
They use optical or magnetic encoders to track rotation. These sensors detect how far the transducer shaft has turned from a defined zero or starting point, usually the first movement of the fastener.
Some models measure angle within a ±360-degree range. Others use a through-shaft design, allowing continuous rotation with no limit. This is ideal for powered or robotic tightening tools that complete multiple revolutions quickly.
That kind of precision helps engineers understand how the joint behaves as it’s being tightened. If a tool rotates too much without an increase in torque, it may point to a stripped thread or material deforming under pressure.
Rotary transducers are especially useful in:
- Automated production lines
- Robotic assembly cells
- Automotive component manufacturing
- Industrial machinery and electronics assembly
Data from these tools is often recorded and analysed. That helps teams identify problems early, maintain quality and meet compliance standards. At Crane Electronics, our CheckStar Multi rotary torque transducer raises the standard for accurate torque and angle measurements in many varied applications. Browse our full range of rotary torque transducers.
Measuring angle with Digital Torque Wrenches
Many modern digital torque wrenches have built-in sensors that measure angle as well as torque. Angle tracking will start when the snug point is detected. Some digital torque wrenches allow you to define this point manually, while others start automatically.
These tools use inertial sensors such as accelerometers to track angular movement. They provide a compact and highly reliable way to measure torque and angle together. Many digital torque wrenches provide engineers with a live readout on a digital display to give them immediate feedback.
Digital torque wrenches are suitable for quality-critical tasks such as:
- Aerospace assembly and maintenance
- High-end automotive engineering
- Medical device manufacturing
- Production spot checks and audits
Given their compact design and ease of use, digital torque wrenches are best suited to environments where multiple joints need to be measured and accuracy is crucial. If you need to digitally record angle and torque measurements, our WrenchStar Multi digital torque wrench is a reliable, robust and versatile solution. Browse our full range of digital torque wrenches.
Why choose Crane?
With more than 50 years of experience in torque and angle measurement, Crane Electronics is a global leader in torque measurement. We provide manufacturers and engineers across a wide range of industries with the tools they need to ensure precision, safety and reliability at every step of the assembly process.
If you have any questions or would like any assistance with choosing the right measurement tools for your application, please contact a friendly member of our team.