Understanding the level of torque you are applying to a nut is excellent for the stability of the structure. It is not ideal to use either too little or too much. If you apply very little torque, then the nuts will be loose and insecure. On the other hand, too much of it will cause the threads to strip along the belt. You have to know the appropriate amount of torque to apply. To achieve this, therefore, you have to understand how to read it. In this article, I am going to demonstrate several ways to do the reading.
How to read a torque wrench
There are different types of torque wrenches and hence various ways to read them. They are as follows:
Reading the Dial Torque Wrench
- Find the meter.
It is at the bottom of the wrench, and it has both the numbers and a pointing arrow. These numbers signify the amount of torque. The unit of measurement can be either in foot-pounds or Newton meters. You can determine the amount of torque by looking at the point where the arrow crosses the number. When you are not using the wrench, or when it is stationary, then it should always point to a zero position.
- Observe the arrow.
To achieve this, turn the wrench around a nut or a bolt. The arrow will also move, and this will represent the amount of torque you are asserting. Avoid turning the wrench vigorously as it will lead to damage to the bolt.
To get an accurate reading, look at the arrow directly from above. If you read it from a different angle, then you will not get an accurate reading!
Other types of these wrenches come with a memory arrow that follows the main one. It is always at the highest torque level to help identify the maximum torque that you were applying previously.
- Make the reading visible and readable.
The beam of the wrench has a lot of lines drawn at close range to each other. It makes the reading of the same to be hard. You can always enhance the accuracy of your results by placing the tape on the beam. It is advisable to use such tape, especially if your wrench does not have a memory arrow. Placing the tape close to the line will make it easier to read.
Whenever you want to purchase a torque wrench, always consider looking for one with a memory arrow. That is because you will not lose the level of torque even if it disengages in the process. Alternatively, you can buy one without the memory arrows, but always remember to have a tape for deployment.
Reading a Digital-Read Torque Wrench
- Consult the instruction manual.
Every digital tool or machine usually comes with a user-friendly manual. It contains all the information necessary to operate the machinery. The manual should tell you how to adjust and read your torque. It is a one-stop-shop information center containing everything that you need to know about your wrench.
After reading the manual, proceed to prepare the wrench. The first thing to do is to clean the threads of the bolts that you want to torque. Do not use tape or any lubricant to clean it.
Other advanced types of digital torque wrenches feature more settings that affect the vibration and sound levels! You should, therefore, understand how to use and to adjust all these types of tools. On the contrary, you might even find it difficult to use and read either of them.
- Set the desired amount of torque using arrow keys.
To set or adjust or set, press the up or down arrows to change the torque setting. Continue pressing and adjusting until you achieve the level of torque that you desire. I would remind you not to set it loose as it would leave the nuts shaky. The opposite is also true, as too much of it will damage the threads of the nuts.
- Press the percentage (%) key to set the tolerance parameters.
Some but not all-electric torque wrenches will not have this feature. The tolerance parameters will help set the torque levels with a lot of precision. They allow one to set the warning before it reaches the desired torque levels. To understand how the tolerance parameters work, here is a brief explanation:
Assuming that you set it to 20%, then the wrench will give out a signal by lighting and vibrating when you are within that level. To adjust it, first, press the percentage key and use the arrows to set it as per your desires.
Tolerance parameters help one to achieve precise torque levels.
- Know when to stop!
If you achieve the torque level as you had set it, the wrench will notify you of the same. You can get the notification in any of the following ways:
- Vibration.
- Light, and
- Sound.
When the notification comes by, then you should stop turning the nut further. You may end up damaging its threads and even the nut. The other impact of not halting the exercise is that you may damage the wrench as well. Since you had already set the tolerance parameter to given predictable levels, then you should know when to stop whenever you are in range.
Reading a Micrometer Torque Wrench
It works on the same principle as that of a micrometer screw gauge. The steps to follow and to read the torque are:
- Rotate the knob in an anti-clockwise (counter-clockwise) direction.
The knob is at one end of the torque wrench. Turning it will loosen the tool and hence allow you to rotate it. Before adjusting the torque settings, always loosen the knob. Failure to do so may shorten the lifespan of your tool. Avoid turning it vigorously, or rather be gentle until you hear it click, then stop the process and read the measurements.
- Look for the numbers above the wrench handle.
There are two sets of numbers listed vertically on both sides of the wrench. The two numbers bear different units of measurements. One group is in foot-pounds and the other in Newton meters. The numbers that are listed vertically are usually known as the Main scale. They represent the level of torque that you set the wrench to and rounded off to the nearest ten units.
- Look for the numbers on the wrench’s handle.
They appear wrapped around the handle. These numbers are the ones known as a micrometer. They usually measure the second number and provide a more precise torque setting.
When getting an accurate level of torque measurement, first, you should get to the range with the main scale numbers. From there, the micrometer numbers will point to the exact level of torque that you need to apply.
When reading the measurements, always prioritize the micrometer scale as it is more accurate than the Main scale!
- Adjust the torque setting.
You will achieve this by turning the handle in an anti-clockwise direction. Turning it in a clockwise direction will reduce the torque setting level, and the opposite is true. To achieve the most optimum level, turn it in an anti-clockwise position, but do not go to the extreme points!
When you turn the handle, it will affect both the Main scale and the micrometer numbers. Rotating the handle will make it move up and down. The numbers on the micrometer will also go and shift as the adjustment happens.
- Adjust it for precision!
When the Main scale and the micrometer scale are in unison, then you will have accurate readings of your wrench. You can do this by adjusting the vertical line on the handle to the one above each number on the micrometer scale.
- Tighten the knob in a clockwise direction.
It is at the end of the wrench. Once you achieve the desired level of torque setting, then you should tighten it by turning in a clockwise direction. Such action will also set the torque on the wrench. You can perform all the adjustments by turning the knob in any desired direction.
- Wait for the click.
You will know that you have the correct torque setting when you hear it click while adjusting it. When the sound comes on, then you have to stop further adjustments. That is the optimum point where you will have the maximum level of torque on your wrench! I would always advise you to turn the knob gently so you can hear the click and to stop in due time.
When you finish your work, then you should set the wrench back to the lowest torque levels. It helps to eliminate the tension in the mechanism and hence gives your tool a long useful life.
Conclusion
Reading a torque wrench can be somewhat a complicated process. The electronic models can be easy to use since they mostly come with a user manual. Others, such as the micrometer torque one can present a real challenge when reading. That is because the readings on the Main scale and the micrometer have to rhyme. However, with a little practice, you should be able to set and to read the measurements!
Richard is a tool expert guy. Especially love to share the experience with others. That’s why he created this blog.