Tachymètre Bezel List - Speedmaster Uses [tachymeter]


Could I ask that you guys help me compile a list of practical uses for the tachymètre bezel with descriptions.

I'd like to keep editing this post and put together a long list.


1. Speed with Fixed Distance

Knowing the distance between A & B as 1 Mile or 1 KM. Start the chrono at point A and stop at point B.

The speed will be represented.

For example 45 seconds would be 80 Miles per hour or 80 KM per hour.


With any of these if it's doubled like A & B is a 2 mile mark then you need to multiple by 2.

So 2 miles at 45 seconds reads 80 MPH multiple by 2 gets you 160 MPH


If the time for 1 mile is over 60 seconds then you need to divide by times around the dial +1.

So if it's 1:45 you get 80 then you divide by 2 since it went past the 60 seconds mark once.

It shows 80 divide by 2 is 40 miles an hour.


2. Distance with Fixed Speed

Driving 65 MPH start the chrono and when the hand reaches your speed (65 MPH) you have now gone 1 mile.

This can be done with KM as well.


3. Production Per Hour

If it takes under a minute to create something like in a factory you start the chronograph and stop when finished.

If it takes 45 seconds to paint a product then you can make 80 an hour.


From my understanding if it takes 2 minutes + 45 seconds, you need to divide by times around the dial +1.

So you would need to divide by 3. So it would be roughly 26.6 painted per hour.


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Any more to add to the list. I could actually see myself using number 2 on the highway if I need to find an exit or number 3 If I'm doing something and want to figure out how long it will take.

 

While I admit I’ve never taken the time to fully understand the details, I take it that a tachy bezel that rotates can be used for other things - taken from wiki:

“Some tachymeter scales are on a rotating, indexed bezel. This allows two additional modes of use: The tachymeter bezel can be aligned with a free running second hand, and, more subtly, can be used to find the average speed over longer times/distances. Set the rotary bezel index to the position of the minute hand, note the current mileage/distance. Glance at the position of the minute hand on the tachymeter scale 60 units of distance later, and average speed will be indicated. A little mental math allows interim averages, easiest at 1/4 (15 unit) and other integer values. Alternatively, instead of using minute hand, align index bezel to the second hand and observe passing one unit of distance when position of the second hand will then indicate average speed.”

 

You lost me here:

One full rotation (one minute) per mile is 60 mph. 1-1/2 rotations would be 40 mph (which would be pointing at the 120 mark at the '6' position). 1:45 would be just under 35 mph. So that procedure does not yield accurate results.

 

So if you are timing something
A -> B it's 1 mile.
But it takes 1 minute and 45 seconds on the bezel you get 80 so you need to dived by 2 which gets you 40 but you are right it comes out to 35 or so when I use a 3rd party source so maybe it needs to be kept on a 60 second scale.

This is another reason I need some more eyes on my post to figure out how to use this scale.

 

As you go about trying to make sense of the tachymètre scale, you can use this equation to check your work:
3600 ÷ seconds
So:
10 sec => 360
60 sec => 60
90 sec => 40
105 sec => 34.2857
120 sec => 30
And so on.

 

There are quite a few variations of item #1 in the first post (Speed for a fixed distance).
Pretty much anything in life that has a pace, rate, or flow to it.

For example, you could measure how fast someone types (words per minute) using a tachymeter.
To do this, you could use a fixed paragraph of 15 words, then use the chronograph stopwatch function to measure how many seconds it takes to type that paragraph, then divide the number shown on the tachymeter by 4.
So, if it took a whole minute to type 15 words, then the tachymeter would show 60, 60 divided by 4 = 15 words-per-minute.
And, if it was done in 15 seconds, then the tachymeter would show 240, 240 divided by 4 = 60 words-per-minute.

Another example, you could measure the flow of water (gallons per minute) delivered by your garden hose.
Fill up a 5 gallon bucket with your hose, time it with the chronograph, divide the tachymeter number by 12.
So, if it took a minute to fill up the 5 gallon bucket, the tachymeter would show 60, 60 divided by 12 = 5 gallons-per-minute.

.

 

@Hands90

to explain miles per hour easier...

on most freeways there are mile markers. Start the chrono when you pass one and stop when you pass another. If it’s been 60 seconds then 60 miles per hour. As 60 seconds in an hour. If it takes 30 seconds your going 120. Or 2 miles a minute. It’s a logarithmic scale. Hence 15 seconds is 240 miles an hour.

 

*tosses all my old college math textbooks in the trash can*

"Whelp, I best be dropping out of engineering now 'cause I've been doin' math wrong for the last 35 years. I hope that bridge doesn't fall down anytime soon."



(hint -- it's a linear equation)

 

Aww sh*t somebody ‘bout to ask a bystander to “hold my nerd glasses so they don’t get broke”


Here:

 

the scale is not the same and represents a value that is getting increasingly higher over a uniform distance, while it’s growth rate is not the same over distance.
What else do you call it.



change years to seconds and the tachy value to the vertical scale.