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Discussion Starter #1
I want to convert a true 24 hour quartz watch to do the following:
1. For the hour and minute hands to go backwards.
2. for the minute hand to go around the dial every 72 minutes or 20 times a day.

are any or both of this two alterations possible to do for a watchmaker with a quartz movement? how about a mechanical movement?

thanks

Marc Adrian
 

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marcadrian said:
I want to convert a true 24 hour quartz watch to do the following:
1. For the hour and minute hands to go backwards.
2. for the minute hand to go around the dial every 72 minutes or 20 times a day.

are any or both of this two alterations possible to do for a watchmaker with a quartz movement? how about a mechanical movement?

thanks

Marc Adrian
Hmmm... you got me curious about the application for this watch! :)

Quartz: I have seen "fashion" watches that run backwards, but wouldn't know any movement number or designation. Next, in order to change (extend) the length of a displayed hour from 60 minutes to actually taking 72 minutes, you'd probably have to change the frequency of the crystal. Most quartz watches run with an oscillator at 32,768 Hz (2^15). Therefore, you'd have to change that oscillator to a frequency that would slow down the watch by a factor of 0.833333 (60/72). However, I doubt you'll easily find an oscillator with 27,306.66667 Hz (if I did the math right).

Mechanical watches are a different story. Maybe changing the gear ratios on a mechanical movement would help get you there (based on "standard" oscillation of the balance), but I wouldn't know a watchmaker who would be able to do that for you.

Now let's hear what you want to do with such a special watch?

Cheers

Matt
 

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I remember reading an article on the www about a watchmaker who made a couple of watches for an american Mars probe controller team. They had to do shiftwork relating to Mars time. A Mars day is significantly longer than Earth days (can´t remember how much though). Electronic watches were not possible because of costs but this watchmaker managed to manufacture mechanical watches for the task.
 

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Discussion Starter #4
thanks for your responses, a 20 hour watch would follow the time keeping of mesoamerica, so that if you made a dial using the aztec calendar on a 24 hour watch you would in fact have a mesoamerican watch, as the day simbols are the same as the hour simbols. Of course on a clockwise watch I would need to invert the calendar design as it is made to be used in a counterclokwise fashion.

Which is probably what I will end up doing. so i will post my next question now.

cheers

marc adrian
 
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