Torque Angle Gauge: How to Use It?

This tool is essential for applications and fasteners that must be torqued using the torque and angle or TTY (Torque To Yield) method. In this article, I will tell you all you need to know about this tool.

Let’s begin!

What is a Torque Angle Gauge?

A torque angle gauge usually measures the angle of rotation applied to a fastener as you tighten it.
Some digital torque wrenches measure torque and angle; however, the most common type of torque angle gauges don’t measure torque, they only measure the angle, and they are used after you have torqued the fastener using a torque wrench.

How Does it Work? Working Principle

Torque angle gauges are named after the torque-angle procedure for tightening fasteners. Besides, TTY fasteners are often tightened following this procedure.

Let’s take a look at both concepts:

Torque-Angle

The torque-angle torquing method combines torque and angle measurements to ensure accurate and consistent tightening. When using this method, a torque wrench is first used to tighten the fastener to a specified torque value, called pre-load. Then, an angle gauge is used to turn the fastener a certain number of degrees beyond the initial torque value. Friction, lubrication, and other external factors can affect the accuracy of torque measurements.
When you only use a torque wrench, friction between the fastener and the surface being tightened can create a significant margin of error in the torque reading, resulting in over or under-torquing of the fastener and the assembly, which can lead to joint failure and other problems.

When using the torque-angle method, the pre-load torque is minimum, reducing the margin error to insignificant values. Once that tightening value has been reached, the fastener is turned a certain number of degrees, creating a precise and consistent torquing.

During the design stage, engineers calculate a part’s torque specs, they calculate how much clamping force is created by turning the fastener, eliminating the friction variable. Besides, this technique adds an extra level of accuracy, as the fastener torque is double-checked, first by applying a given torque and then the correct angle.

Torque-to-Yield (TTY) Fasteners

These fasteners are torqued over the fastener’s material yield point. This means that these fasteners are torqued to the verge of suffering plastic deformation (damage) as they are tightened, reaching their highest clamping force, which has been proven to be the best way to achieve stability in applications that work at high temperatures or endure extreme temperature changes, like cylinder heads, for example. As TTY are torqued to a point where they become stretched permanently, these fasteners can’t be reused since re-tensioning them is unpredictable and unreliable as they are on the limit from suffering permanent damage. The torque-angle method is the best way to torque these fasteners; however, it’s incorrect to assume that all fasteners with torque-angle torque specs are of the TTY type.

Do I need a Torque Angle Gauge? Common Applications

Torque angle gauges are commonly used in applications that require precise and accurate torque values and parts that need to be torqued using the torque-angle method, such as:

Automotive industry:
Torque-angle is commonly used for tightening cylinder heads, connecting rods, crankshafts, and other components that need accurate tightening.

Aerospace industry:
For securing aircraft engine parts, airframes, and other critical components.

Manufacturing industry:
To assemble heavy machinery, equipment, and other mechanical components and structures.

Construction industry:
For tightening bolts in bridges, buildings’ frames, and other structures.

Heavy Machinery, Mining, and Oil Industries:
For tightening bolts and nuts in heavy machines, pipes, appliances, oil rigs, and others.

In conclusion, a torque angle gauge is a tool that can’t miss in any professional toolbox. When you work with machines and structures that have torque-angle torque specs, you won’t be able to do the job without one of these tools.

Types of Torque Angle Gauges

Mechanical

Mechanical torque angle gauges are simple; they consist of a pointer that rotates around a graduated scale marked in degrees. They have a female square drive on the top (the part marked with numbers) to insert a breaker bar or a wrench and a male square drive on the bottom so that you can attach a socket or adapter and tighten the fastener.

They come in different sizes and with different types of square drives; the most common size is the one with 1/2″ square drives. The pointer is connected to an “L” shaped rod, also called an L-handle, that comes out from the side of the gauge that is used to fix the desired angle. This screw is tightened or loosened by a small screw, also located on the side of the tool.

Digital

There are a few types of digital torque angle gauges; I will describe the two most common types below.

• Electronic torque wrenches: These are one of the most common digital torque angle gauges. They are digital torque wrenches that measure both torque and angle. You just have to set the desired torque or angle, depending on what you want to do, and you will read the value on the display in real time.
• Digital torque-angle adapter: They work as mechanical torque angle gauges, just that the angle is read on a digital screen, and they have some cool features like you can set them to beep to alert you that you have reached the desired angle.

How to Use a Torque Angle Gauge?

Mechanical Torque Angle Gauges

1. Use a torque wrench to tighten the fastener to the specified torque value.
2. Attach the desired socket to the device’s male square drive.
3. Find a bolt or a firm metal part that can hold the L-handle in place as you tighten the fastener.
4. Place the socket you inserted into the gauge’s socket on the fastener you want to tighten.
5. Loosen the screw on the side of the tool, and make sure the gauge is set to 0 and the L-handle won’t move. When everything is set, double-check that the pointer is set to 0 and tighten the bolt to secure the L-handle.
6. Attach a breaker bar or ratchet wrench using a socket that matches the size of the torque-angle female square drive.
7. Rotate the breaker bar clockwise until the pointer marks the desired angle. Make sure that the L-handle doesn’t move or slip from where it’s locked.
8. That’s all; you have just tightened the fastener to the specified torque and angle.

Digital Torque Angle Gauges

1. Attach the desired socket to the tool’s square drive.
2. Set the desired torque value on the electronic torque wrench’s menu.
3. Tighten the fastener until it’s torqued. Depending on the tool, you will hear a beep or see a light flash when you have reached the desired torque.
4. Remove the tool from the fastener and set the desired angle.
5. Rotate the torque wrench and check the screen; you will see the angle increase in real-time. Most electronic torque wrenches will beep or flash when you have reached the desired angle.
6. That’s it!

Dial Torque Angle Adapter

1. Use a torque wrench to tighten the fastener to the specified torque value.
2. Place the desired socket to the device’s male square drive.
3. Attach a ratchet wrench or a breaker bar using a socket that matches the torque-angle female square drive size.
4. Depending on the tool, you will just read the angle on the screen, or you will be able to set a desired angle as you would on an electronic torque wrench.
5. Start rotating the breaker bar clockwise until you read you have reached the desired angle, or the tool flashes or beeps if that function is available.
6. Congrats! You have tightened the bolt to its precise torque specs.

Torque Angle Gauge vs. Torque Wrench

Torque angle gauges and torque wrenches are complementary tools. Even when measuring the angle is more effective and reliable than measuring torque, we, as final users, don’t have all the information needed, the time, and the skills to calculate how much angle a given assembly requires. However, we all understand torque, and finding how much torque a fastener or a joint needs is much easier.

The torque-angle method is used when user manual specify the precise value, and that’s why these tools complement each other so well. It’s as simple as torquing the fastener and then setting the angle, so there’s no competition about which one is better; both tools are necessary to work with precision parts.

Mechanical torque angle gauges are extremely simple and affordable (in the range of $20), but if you want a tool that does all in one, you can always buy an electronic torque wrench that measures the angle. They go from $150 and up, depending on their quality and precision.

Conclusion

Whether mechanical or digital, torque angle gauges are essential tools for professional jobs where you need to tighten fasteners accurately according to torque and angle specifications.
They are also important to tighten TTY fasteners to ensure you are tightening them to their maximum clamping force without breaking them. In my experience, mechanical torque angle gauges are the best choice to go in terms of reliability and price. I have been using the same ½ mechanical torque angle gauge for years in my garage, and it still works perfectly.