How do timing machines work and how is the data interpreted

SpringDriven

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That is a big question.

A timing machine listens to five knocks or shocks in the escapement in the running of the watch.

Look at slides 37 to 40.

These impacts, in relation to the frequency of the watch (4Hz or 28,800 BPH for example) are compared to a source timing signal, usually a quartz timing reference.

The timing of these impacts also determines the beat error. The escapement is most efficient when in beat, that the impacts to both sides of the pallet fork are equal in timing, which indicates that the impulse stone is centered in relation to the escapement. When the impulse stone is favoring one side or another, the watch is out of beat, as one side is favored and is less efficient.

You can hear beat error in clocks with a pendulum. The sounds will be out of sync with each other. When in beat the tick tock of a clock will be equal.

This is keeping it simple.
 
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SpringDriven

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A side, to how is the data interpreted.

A modern quartz watch runs at a frequency of 32KHz.

A modern watch typically runs at 4Hz.

You can then comapre the two frquencies to each other. In the case of the timing machine it uses a typically quartz reference signal and compares it to the frequency of the watch placed upon it by listening to the timing of the escapement, those five shocks or impacts.

If the watch is designed to run at 4Hz, then those five shocks should occur within that time, or 40 of them to be precise, as there would be 10 impacts per oscillation.
 
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SpringDriven

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The next and final step of the timing machine is amplitude. That is measured by telling the timing machine the lift angle of the watch. That tells the timing machine the angle of interference that the pallet fork has in relation to the balance wheel.

Typical lift angles in modern watches is 49 to 52 degrees. If you think of a balance wheel that rotates, then you can percieve that as the pallet fork is transferring power to the balance wheel, it is interacting with it. Once the pallet fork runs to the bank, or makes contact with a banking surface, it is no longer in contact with the balance wheel. The balance wheel is now in free swing.

The timing machine knowing the lift angle you entered, and the frequency of the watch, then can calculate the amplitude of the balance by timing the time between the run to the bank phase and the next unlocking phase, in which the balance was in free rotation.

You can determing lift angle of a watch by winding it until you observe that the balance arms are swinging an equal 180 degrees in each direction. Then input lift angles into the machine until the timing machine says that the watch is running with an amplitude of 180.
 
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svenedin

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That is a big question.

A timing machine listens to five knocks or shocks in the escapement in the running of the watch.

Look at slides 37 to 40.

These impacts, in relation to the frequency of the watch (4Hz or 28,800 BPH for example) are compared to a source timing signal, usually a quartz timing reference.

The timing of these impacts also determines the beat error. The escapement is most efficient when in beat, that the impacts to both sides of the pallet fork are equal in timing, which indicates that the impulse stone is centered in relation to the escapement. When the impulse stone is favoring one side or another, the watch is out of beat, as one side is favored and is less efficient.

You can hear beat error in clocks with a pendulum. The sounds will be out of sync with each other. When in beat the tick tock of a clock will be equal.

This is keeping is simple.
4 Hz is 14,400 BPH. A usual beat rate for an old pocket watch is 5 Hz 18,000 BPH
 

SpringDriven

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4 Hz is 14,400 BPH. A usual beat rate for an old pocket watch is 5 Hz 18,000 BPH
I apologize, but your math is off. A frequency is a measurment of one oscilation per second.

Consider a pendulum. From the center point it recieves an impule and swings to one direction, slows, stops, comes back to center where it recieves a second impluse, slows, stops and returns to center. This would be one oscillation, but two beats.


If a watch runs at 4hz, it has eight beats per second.

8 beats per second times 60 seconds = 480 beats per minute.

480 beats per minute * 60 minutes = 28,800 beats per hour.
 
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svenedin

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I apologize, but your math is off. A frequency is a measurment of one oscilation per second.

Consider a pendulum. From the center point it recieves an impule and swings to one direction, slows, stops, comes back to center where it recieves a second impluse, slows, stops and returns to center. This would be one oscillation, but two beats.


If a watch runs at 4hz, it has eight beats per second.

8 beats per second times 60 seconds = 480 beats per minute.

480 beats per minute * 60 minutes = 28,800 beats per hour.
I stand corrected! My maths is indeed off. I am confusing beats with cycles per second. It’s rather late here. Brain not working!
 
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gmorse

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Hi Old rookie,

Whilst there are five 'shocks' in the sound of a lever escapement, as you can see from the waveforms, there are only three which can be easily distinguished and these are perhaps better described as the 'unlock', the 'impulse' and the 'drop'. Some timing systems will show you the actual waveform and/or allow you to hear the real sound of what's happening, rather than just generating a beep, which can be useful in diagnosing escapement problems.

Regards,

Graham
 
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karlmansson

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Put in more general terms, a timing machine is used at the start of a service to determine the state of the movement to some extent (I at least do this to see what I'm dealing with) and then again after the movement has been fully cleaned, reassembled and lubricated. There is no use in trying to adjust a watch to the degree that a modern timegrapher offers if the watch still has mechanical/cleanliness issues. The timegrapher will only tell you the performance of the escapement and not the actual time the watch will show. A loose cannon pinion will for instance have you chasing your tail if you judge time keeping just from referencing the position of the hands to known good time keeper.

Others before me have explained the different aspects of the wave forms and so I shant. What you do with the data the machine provieds you with is depenent on the combination of the data and what you have seen in the watch during service. There is also a set of best practices that is beyond the scope of this thread on in which order to adjust for certain faults in an escapement. The most basic adjustment would be to adjust the base rate of the watch in, say. the dial down position, to get it close for further adjustments. That would be done by moving the regulator arm until you have the desired rate. Modern timegraphers also have the option to reposition the pickup so that the watch can be tested for variance in rate depending on the position of the watch. This is what "adjusted to six positions" on a watch means. Dewey Clark has written a very comprehensive document on static and dynamic poising on this matter. I highly recommend finding and reading it.
Beat error is another common adjustment where vintage watches usually rely on rotating the hairspring collet on the staff and some modern movements have a moveable stud carrier to accomplish the same. Then comes more involved and delicate adjustments such as correcting aspects leadning to variance in beat error depending on the position of the watch or position of the regulator arm, which is also something a time grapher will tell you.

Finally, a timegrapher with a "paper strip" function will show you a line of dots where you will be able to spot variances in rate that are inconsistent in relation to the rotation of a certain wheel or pinion, making the troubleshooting process a little easier and provides clues for your Sherlock Holmes like horological inductive reasoning. :).

Best of luck!
Karl
 

DeweyC

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Dewey Clark has written a very comprehensive document on static and dynamic poising on this matter. I highly recommend finding and reading it.
Beat error is another common adjustment where vintage watches usually rely on rotating the hairspring collet on the staff and some modern movements have a moveable stud carrier to accomplish the same. Then comes more involved and delicate adjustments such as correcting aspects leadning to variance in beat error depending on the position of the watch or position of the regulator arm, which is also something a time grapher will tell you.

Finally, a timegrapher with a "paper strip" function will show you a line of dots where you will be able to spot variances in rate that are inconsistent in relation to the rotation of a certain wheel or pinion, making the troubleshooting process a little easier and provides clues for your Sherlock Holmes like horological inductive reasoning. :).

Best of luck!
Karl
Karl,

The paper (which received important input from members of this forum) can be found here:

 
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