Deconstructing the Tachymeter

Alright today let’s talk about the tachymeter complication.

A tachymeter gives a timepiece a sporty look, something that when you look you associate with sports such as racing or for the military.

It add lovely contrasts to many timepieces, making the overall look more sophisticated.

Though a lovely complication which adds dimension to your timepiece, it may be totally foreign or alien to some on how to use it.

Like seen from the below picture, my Seiko Criteria SNDG13P1 (which I will write about soon)

 

Some people go out having their timepiece without ever using the tachymeter function.

To a major share of watch uses, they may simply purchase a timepiece with the tachymeter function due to the fact that it add aesthetic value to their timepiece.

So let us cover how a Tachymeter actually works.

A tachymeter scale is a scale sometimes inscribed around the rim of an analogue watch. Usually with Arabic marking around the dial as well.
 
This function is used to either measure a distance based on speed or speed based on travel time. The markings have spaces in between them on the tachymeter dial are consequently proportional to 1/t where ‘t’ is the elapsed time.

A tachymeter’s performed function is independent of the unit of distance be it kilometres, miles or any other only as long as the unit of measure is equivalent for all calculations. In essence, a tachymeter is a way or means of converting ‘elapsed time in seconds per unit to units per hour’.

To get a little mathematical below is some info on calculations to work it out;

“To use a tachymeter function to measure speed, start the chronograph at a starting marker of a known distance. At the next position, the point on the scale adjacent to the second hand indicates the speed of travel between the 2. The typical scale on a timepiece converts between the number of seconds it takes for an event to happen and the number of times that event with occur in a hour. The formula to create this

kind of tachymeter scale is     T = 3600/t   

Where ‘T’ is the tachymeter scale value and ‘t’ is the time in seconds that it takes for the event to occur and ‘3600’ is the number of seconds in an hour.

So lets work out an example, if it takes 35 seconds to travel 1 kilometre then the average speed would be 103KM per hour. Do take note that the tachymeter scale only calculates the average speed.”

So with that, we are more or less through with the practical of a tachymeter.

Lastly, just some history, the first rotating bezel tachymeter was introduced by Heuer, now Tag Heuer which was back in 1958.

By the late sixties chronograph timepieces where sky rocketing, demand grew invariably and watch manufacturers around the globe were contesting to opportunities to patent automatic versions and wanted exclusive rights. It has to be known that without the chronograph the tachymeter complication would have no place as well.

Let me share a little fascinating history on some very lovely chronograph movements which came into being.

Around that time Breitling, Heuer and Hamilton partnered up with Dubois Depraz to develop the first ever self-winding chronograph. It was a clandestine affair in which only a handful of professionals involved on a need to know basis. This great development was unveiled in Geneva and New York on 3rd of March 1969. Called the Chrono-matic, the Calibre 11 movement would wind itself using an off centre micro rotor.

Soon enough, Zenith had produced the El Primero (Which might I add, is absolutely stunning!) which used a central mounted full rotor and was capable of measuring time to one tenth of a second.  Seiko the Japanese giants also released their automatic chronograph called the 6139 Auto-Chrono.

Out doing themselves once again, Seiko created the world’s first quartz watch, a giant breakthrough in Horological history, thanks to this hefty invention it somewhat marked an end and seemingly rendered chronographs virtually obsolete with the Seiko Quartz Astron 35SQ.

Back to our modern day and age, the chronograph is making a comeback and is appreciated by many once again.

With many lovely pieces from Tag, Seiko, Breitling, Hamilton and so on.

Though some of us may not entirely know how it functions or its practicality, it may serve as an aesthetic feature. Nonetheless the tachymeter is a lovely complication, you will never know when it may come in handy.