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

[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

SpeedyTachy-1.jpg

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.

LancoTachy-1.jpg

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.