Reading Your Bezel......Tachymetre/Telemeter

[GTS Dean]

The answer is YES! (if you're willing to wait)



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[Npena240]

Great info. Thanks

[Jschothorst]

Originally Posted by Tools

The Tachymeter or Tachometer bezel on your Chronograph is a simple calculator for determining approximate speed in MPH/KPH, or determining a simple rate of production.

For speed estimates, you need a measured mile or kilometer. As the object you want to time enters one point on the measure (milepost) start the stopwatch function of your chronograph. When it reaches the next milepost, stop the second hand. An estimate of mph is read off the bezel.

Here is an example. The time to travel the measured mile took 20.2 seconds or ~179 mph



Rate of production can also be determined. If you are watching an assembly line, or timing an event (say chugging a bottle of water), you start the timer at the beginning of the event. You stop after the end of the event, or when another product comes off the assembly line.

Using our example above; if 1 widget was made during the 20 seconds timed, then 179 widgets are being produced per hour. Or you are chugging a bottle of water at the rate of 179 bottles per hour.

There are more than one type of bezel or scale available for a chronograph. Some are marked with a Telemeter bezel. In the case of our next example below, it is the red scale. When a visual cue at a distance is observed, the timer is started. The timer is stopped when an audible cue that corresponds to the observation is heard. The approximate distance is read off the scale.

Using our example below let's say that a lightning strike is observed, and then the event is timed until the thunderclap is heard. In this case, ~36 seconds, and our scale is calibrated in kilometers, so reading off the telemeter scale, distance is slightly over 12 kilometers away.

In a military application, you can see the flash of the artillary, time the event until you hear the sound, and be able to know the approximate distance away the artillary is placed.



One last type of bezel encountered is the decimal bezel. This is easily identified because it is calibrated from 1 to 100, Using this bezel, time is read off the bezel in tenths, or hundreds of a minute.. If you time an event and the second hand is stopped at exactly 30 seconds, the decimal bezel would reflect .50 of a minute.

That's a nice watch and thanks for the information

[50hz]

very cool info, appreciate this post.

[lavaman]

Ok dumb question: does all of this still apply if what you are timing takes longer than 60 secs to complete a circuit? For example, if I wanted to time a lap of an F1 circuit, and I start the timing at pit row.....

[lavaman]

Ok disregard, I just reread where it says...measured mile

[skprd13]

Excellent post! Learn something new everyday.

Aloha from Kauai.
Tom

[sueno213]

Very good info. Why does Breguet Transatlantic xx1 have indices every two minutes on the 30 minute scale?

[idle spectre]

nice read

[brinktime]

Thanks for the fun sunday-fact :)

[Dimik]

Hi guys, thank you for providing guidance on how to read the bezel. But I have a question about how you would read it if the process is longer than a minute? E.g. 1 car completes a 1 km lap in 1:30. What is the speed then?

[Mellow Mike]

The answer is 40 kph. The time is 90 sec. divided by 2 shows speed of 80 kph then divide 80 by2 = 40

[Goschi10]

Originally Posted by Gurmot

Another great article, and very useful too but aren't we forgetting another member of the Speedy bezel family?

Here's my 1967 cal 321 Speedy with a Pulsations or Doctor's bezel. It is used to measure heart-rate by recording the time it takes for 15 heart-beats. The watch is stopped after the 15th beat and the equivalent BPM is displayed.

What do you reckon to this one?

Cheers - Simon

This is an absolutely incredible piece

[heritagewatchdealers]

Thank you!

[watchprenuer]

great info thanks

[alexmiranda]

Very informative post, showed this to a friend which is also an Omega fan.

[Pedrovasques]

How can you calculate on a 116500?

[schoolboy]

Originally Posted by Pedrovasques

How can you calculate on a 116500?

The exact same way