Find Out How a Vernier Scale Works: Know Your Tools Better

How Does a Vernier Scale Work

“Vernier Scale” is the name of an amazing piece of technology that has transformed our measurement process like magic. Since French mathematician Pierre Vernier invented it in 1631, the vernier scale has made so many wonders possible that we take them for granted nowadays. But I’m sure many of you want to know the secrets of vernier scales like how does a vernier scale work, how to read a vernier scale, what exactly is the use etc. That is why today, we will answer all those questions and give you a better overview of this amazing and essential technology.

By the end of this article, you’ll have solid ideas about the principle of working on a vernier scale, how to take an accurate reading on a vernier scale, and why we need this. So without wasting any more of your time, let’s get started.


What Is a Vernier Scale

Vernier scale is basically a kind of visual aid to measure more accurately. We’ve been using a standard ruler for hundreds of years. But there are some limitations to taking measurements with a traditional scale. We can measure as little as 0.01cm with a regular measuring scale, right? Now, if you have to measure some length more accurately that is smaller than 0.01cm, how do we do it?

Well, here, a vernier scale comes into play. This scale uses mechanical interpolation to increase resolution, reducing measurement uncertainty and human errors. In a nutshell, a vernier scale is a small, movable auxiliary scale attached to the main scale and calibrated specifically to indicate fractional parts of the subdivisions of the larger scale.


How Does A Vernier Scale Work

The most common example of a vernier scale is a vernier caliper or a micrometer. Using the vernier scale, this handy device can take precise measurements up to one-hundredth of a millimeter or one thousand of an inch. But how does this work? Let’s have a look.

The vernier scale works by using the alignment of line segments displaced by a small amount to make fine measurements. The scale is designed to help you take an accurate measurement with the help of your eyesight and some calculation only. You’ll need two scales to complete the measurement process, one is a regular scale (main scale), and the other is? You guessed it, the vernier scale.

The vernier scale is marked with divisions slightly smaller than the divisions of the main scale. The number of the markings varies with the device you are using. If your vernier scale has 11 markings for every 10 on the main scale, that means there are 10 divisions/segments on the vernier scale for every 9 on the main scale. In this case, the vernier divisions are each 90% of the main scale lines/divisions. Now, the scale is designed in a way that the “0” line and the “10” line on the vernier could pair up with marks on the main scale, but none of the other divisions would.

Most of the instruments that use a vernier scale have a mechanism that will allow the vernier scale/main scale to move freely relative to the other one. You just have to check for the vernier scale division that will align perfectly with any division from the main scale. In your case, If the 0-line pairs up with a mark, the next first mark of the vernier scale will be 10% short of reaching a mark of the main scale. The same goes for the next marks, meaning the 2nd mark will be 20% short, the 3rd one will be 30% short, and so on.

Both a linear and a circular (rotational) vernier scale follow the same principle. You just have to find the vernier scale reading/mark that perfectly aligns with any mark from the main scale. The rest is calculation.


How To Read A Vernier scale

Now, let’s have a look at how to get the actual reading from a vernier scale. Though it may sound a bit complicated, the measurement/reading process is pretty straightforward. Let me explain.

Here are the steps you’ll need to follow to read a vernier scale properly.

Step #1: Read the main/normal scale and find out the last whole increment visible before the 0 (zero) mark.

Step #2: Now read the secondary scale (vernier). Look for the scale mark that lines up best with a mark on the main scale.

Step #3: Add the two readings to get the final measurement.

For example, imagine the 0 on the vernier scale goes a bit further than the 5 on the main scale. If the vernier scale crosses 2 lines after the 5 mark, the reading will be 5.2, and if the scale aligns perfectly with the 5 mark, then the reading will be 5.0. Simple enough? Now, imagine the ninth mark on the vernier scale matches a mark from the main linear scale. So the vernier reading will be 0.09. Now all you have to do is add those two readings, and you’ll get the final reading like this:

Final reading = Main Scale Reading + Vernier Scale Reading 

In this case, X = 5.2 (or 5.0) + 0.09 = 5.29mm (or 5.09mm)

The same principle applies to a circular vernier scale as well. The only thing you need to do differently is you’ll have to rotate the vernier scale to match the markings with the main linear vernier scale.


Why Should You Get One

By now, you already know how a vernier scale works, right? Now, you may be wondering what’s the use. After all, we don’t need that precise measurement in our everyday life, right? Well, you would be surprised to know that our modern technology stands on the development we’ve made so far in measuring many phenomenons accurately. Though you don’t need a vernier scale in your everyday life, you are using the result of accurate measurements even if you are not aware of it.

Let me give you an example. The smartphone you are using uses precise measurements on its components. Otherwise, it would be impossible to get so much computing power within this much-limited space. This is an essential tool for a massive number of technicians and engineers across the globe. If you root for accurate measurement, a vernier scale is the easiest way to ensure that.


Over To You

Vernier scales are one of the easiest ways to minimize human estimation error, where being precise and accurate is a must. This amazing mechanism/tool has turned many imaginations into a reality. No matter where you go, precise measurements are required to move forward.

The ability to measure something accurately has helped mankind progress so far that we’ve transferred our civilization from eating raw meat to colonizing Mars. Can you imagine the power of precise measurements? We can’t even imagine what would happen if the measurements weren’t as precise as today.

No more today. I hope this article proves to be helpful to those who are looking for a bit more insight into these amazing tools. Please feel free to share your thoughts and experiences with us in the comments section below. Thanks for reading this far. Happy measuring to you.

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