# The Beauty of a Tachymeter

Are you familiar with a tachymeter? It’s a fascinating device that you can have a lot of fun with, once you understand what it can do and how to use it.

Have we piqued your interest? Then, let us tell you more about the tachymeter and why some of our latest watches feature them.

**What a tachymeter is**

Essentially, a tachymeter is a mechanism for measuring speed. It does this by using a scale that marks the time elapsed and converts it into the speed travelled.

This handy tool works in conjunction with a chronograph, or stop watch. The tachymeter can be found around the watch’s rim or bezel where it’s calibrated to show the number of seconds in an hour – 3600. The chronograph button will be on the outer edge of the watch face.

**The history of a tachymeter**

It’s easy to trace the origin and development of the chronograph over the years. The very first chronograph was invented by Nicolas Mathieu Rieussec, a French watchmaker, in 1821. It took some time before one of the first wristwatches with a chronograph was manufactured, in 1913. Shortly thereafter, a tachymeter was added. This was a huge step forward and watches with this functionality become popular, particularly with individuals involved in aviation or automobile racing. By the 1930’s, the tachymeter was often a sought-after item. Today it continues to be a feature on many fine time pieces, including our recently-launched 1981 chronograph collection.

The rotating bezels were introduced in 1958 by Heuer. Back then, hardly anyone other than racing enthusiasts and aviators found any use for chronographs and tachymeters. Today, on the other hand, most watches come with these functions, and consumers purchase them even if they only use them to check the time.

Ironically, nobody knows for certain who the father of the AUTOMATIC chronograph was (developed more than a century later). Three different watchmaking firms released the automatic stop-watch in the same year - 1969. However, nobody can point out for certain who first started working on the project.

**The tachymeter’s purpose**

Not only can the tachymeter be used for measuring speed, but it has several other very interesting and helpful applications.

For instance, it can be used to measure the distance travelled based on the speed you’re moving. In addition, a tachymeter can tell you how long it will take you to perform certain tasks.

So, if you’re ready to learn how to use the tachymeter on your watch to its full advantage, read on and we will take you through the steps.

**How to use a tachymeter**

**Measuring speed**

To measure the average speed you’re moving, start the chronograph at the beginning of the distance you want to measure. After you’ve gone one mile (if you’re on a main roadway, you could use the mile markers for reference), stop the chronograph and look at the number on the tachymeter adjacent to the second hand. This will show your speed in terms of the average number of miles per hour.

For example, if you travelled for 50 seconds and the second hand lines up with 72 on the tachymeter this means you were moving at 72 miles per hour.

Wherever you go, this watch feature can be beneficial. Say, for instance, you’re travelling in Europe and want to measure your speed but the distance is in kilometers. Since the tachymeter has a neutral scale, you can use it anywhere. Just stop the chronograph at the end of one kilometer of travel and look at the number indicated on the tachymeter to find your average speed.

Keep in mind that when measuring speed in this fashion, the time elapsed should be anywhere from about seven to 60 seconds since the chronograph covers one minute as it moves around the watch face.

Let’s say you want to measure how fast a DeLorean travels over one mile. Start the chronograph hand when the car takes off and stop it when it crosses the finish line. Where the chronograph points to on the bezel is how fast the car was going. If the DeLorean took 42 seconds to drive one mile, then it was traveling at speeds of 88 miles per hour.

**Determining distance**

The tachymeter can also be used to measure distance, provided you’re moving at a constant speed.

Let’s take the example of travelling on a roadway again. Notice what speed you’re moving at. Imagine you’re going 72 miles per hour. Now, start your chronograph and notice the second hand move until it reaches 72 on the tachymeter scale. The chronograph will show that 50 seconds have elapsed, and this tells you that you’ve travelled one mile during that time.

You can then use this information to estimate the arrival time at your destination. For example, if it took 50 seconds to cover one mile and you know your destination is 25 miles away, then you should arrive in approximately 20 minutes. This is, of course, if you travel at the same speed throughout the journey and don’t encounter any traffic congestion.

**Calculating work time**

An innovative way to use the tachymeter is to calculate the amount of time it takes to do a task, or unit of work. This is assuming that your work effort is relatively constant. Here’s how to do this with a few examples.

Let’s imagine you have a pile of logs that you want to chop into firewood kindling. If it takes you 40 seconds to chop one log, the second hand on your watch will line up adjacent to 90 on the tachymeter scale. This means you should be able to split 90 logs in an hour. However, this could be a tall order since you’ll be quite fatigued by the end of an hour! Therefore, it may be more realistic to take a look at a smaller unit of time such as 20 minutes. Dividing 90 by three tells us you should manage 30 logs in 20 minutes.

You can also measure the time something will take even if a unit of work takes more than 60 seconds. For example, if it takes 90 seconds to make a sandwich this means it takes 45 seconds to make ½ a sandwich. We can then use the 45 second time to say you can make 80 ½ sandwiches or 40 full sandwiches in an hour.

Now that you know the basics, we invite you to take a closer look at these marvelous devices on our watches – the 1981 chronograph collection. Not only does the tachymeter have some very practical uses today, but we’re confident that you’ll find more and more ways to apply it as you explore further what it can do. Enjoy experimenting!

**The Dial. The Watch Dashboard**

Like the dashboard of a car, the dial of the 1981 watch tells you everything you need to know. At the center of the dial—available in black or silver—sits the hour and minute hands. And because the chronograph hand takes the traditional place of the seconds hand, the seconds are instead displayed in a subdial at 6 o’clock.

At the 9 o’clock position is the 30-minute totalizer. This subdial records how long the chronograph hand has been running, up to 30 minutes in total.

Located at the top of the dial is the 24-hour subdial, which serves as a day/night indicator. If the hand on the 24-hour subdial is pointing to “6” then it is 6 AM but if it points to “18” then it is 6 PM. Finally, tucked in between 4 and 5 o’clock is a discreet date window.

For clear legibility even in the dark, the new 1981 Chronograph watch features plenty of luminescent details.