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Discussion Starter · #1 ·
I sent my Omega Speedy Pro in for regulation, and I was called yesterday that it's ready to be returned-- before, it was +11-13 sec/day, now it's been regulated to something like 4.7 sec/day. Since the number is so specific (ie, not 4-1/2 sec), I assume it's done by computer. How accurate are these computer measurements typically? Also, how long is the movement actually hooked up to the computer for these measurements to take place? Seconds? Minutes? Hours?

I initially took this Omega to Swatch in LA for regulation, and when they returned it, they said it was +7.6 sec. In the 3 months since, it never ran slower than +9, usually >10 sec/day. How could they be so far off?
 

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I sent my Omega Speedy Pro in for regulation, and I was called yesterday that it's ready to be returned-- before, it was +11-13 sec/day, now it's been regulated to something like 4.7 sec/day. Since the number is so specific (ie, not 4-1/2 sec), I assume it's done by computer. How accurate are these computer measurements typically? Also, how long is the movement actually hooked up to the computer for these measurements to take place? Seconds? Minutes? Hours?

I initially took this Omega to Swatch in LA for regulation, and when they returned it, they said it was +7.6 sec. In the 3 months since, it never ran slower than +9, usually >10 sec/day. How could they be so far off?
As much as the engineers among us (that would be me :-d) would like movement regulation to be an exact science, it is not.

The main culprits are positional variation and temperature changes.

Our watches run at different rates depending on their positions - dial up, dial down, crown up, crown down, crown left, crown right, and any other odd angle normally encountered in the course of a day's wearing.

They also run at different rates depending on the temperature - faster or slower as their temperature goes up or down.

They are delicate mechanical devices and such variations are the bane of our existence :-s

Here is a picture of my BaliHa'i on my MTG-1000 watch timer:



If you look at the bottom of the display, you will see that the watch is running at a rate of "+000 S/d," or exactly "dead on" with absolutely no gain or loss over the course of 24 hours - based, of course, on about 6 seconds of sampled data and assuming nothing (e.g. position, temperature, etc.) changes.

Does this watch maintain such perfect time when I wear it? Of course not. It's a little bit different every day based on how and how much I wear it, environmental conditions, etc. It's very, very good, but not as perfect as the timing machine says it is.

So, to answer your first question, your watch was hooked up to a timing machine for a couple of minutes and its result is what was reported to you. My machine will only resolve full seconds/day, but more sophisticated machines are capable of tenth second resolution (not really necessary, but we all like accurate sounding numbers, even if they don't mean much - but that's another discussion from an old school analog guy who never really bought into digital ... :-s).

To answer your second question, there will always be an "offset" between what a machine says your watch's rate should be and what it actually is on your wrist when you wear it. Your wear patterns simply do not align with the static testing equipment that was used to regulate your watch. Give the same watch to someone else and they will most likely experience a slightly different rate.

Without taking the time to accurately measure a watch's rate over the course of several days/weeks, then regulating it, then measuring again for several days/weeks and analyzing the results, the best a commercial shop can do is take a "best guess" about the perfect regulation for you. Usually this is a little bit fast because most people prefer a watch that runs a little fast to one that is a little slow.

If all this makes sense, and you want the best results possible, learn how to regulate your watch, buy a timing machine, and prepare for the pursuit of perfect timing to consume a good portion of the rest of your life :)

HTH
 

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Discussion Starter · #3 ·
Thanks for the info!

When a watch is timed with such a machine, do most watchmakers only do it in one position (ie, dial up) or in multiple positions? The fact that I was only give one measurement suggests it was only in 1 position, no?

Also, if a watch can be timed in only seconds or minutes, why can't better accuracy be attained? For example, if mine is +4.7 sec, would it not be possible to tweak the regulation screw a tiny bit more and re-measure? The only way it wouldn't be feasible would be if the movements had to be put back into the case, which I don't believe is the case.
 

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Thanks for the info!

When a watch is timed with such a machine, do most watchmakers only do it in one position (ie, dial up) or in multiple positions? The fact that I was only give one measurement suggests it was only in 1 position, no?

Also, if a watch can be timed in only seconds or minutes, why can't better accuracy be attained? For example, if mine is +4.7 sec, would it not be possible to tweak the regulation screw a tiny bit more and re-measure? The only way it wouldn't be feasible would be if the movements had to be put back into the case, which I don't believe is the case.
Depending on the movement, there can be significant positional variation.

Let's take a hypothetical watch which measures as follows on the machine:

Dial down: +15 s/d
Dial up: -5 s/d
Crown up: +5 s/d
Crown down: -5
Crown left: +15

If only one number is reported to you, it could very well be an average of these 5 positional measurements.

In our hypothetical case, the average would be +5 s/d.

The problem is, "tweaking" the regulation screw a little bit does not yield a linear result for all positions. A small adjustment in one position may result in a big difference in another position.

Without spending a great deal of time, it may not be possible to acheive a better average than +4.7 s/d.

And besides, what it says on the machine is NOT going to be what it does on your wrist.

Please remember, we are talking about a sensitive mechanical device that will change its performance based on how you move every day, what temperature it is, how you rest it when you take it off, how active you are (amount the watch is kept wound), etc., etc.

A matter of a few seconds/day is trivial in the overall scheme of things - and what you observe as +9 seconds today will probably be a little different tomorrow.

Understanding is one thing, obsession quite another :-s
 

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I shoot for plus 4 to 6 seconds a day in a movement that is running well, meaning little variation from one position to another. The reason is somewhat arbitrary; watches are meant to get people somewhere on time, and most people have a better tolerance for being a minute or two early rather than a minute or two late.
For most watches I do three positions, dial up, crown down, and upside down (the 12 o'clock marker down, 6 o'clock up, crown on the left). The first two positions are usually pretty close to each other, and give a good 'rough idea' how sucessful the service was. Why these three positions? Dunno. They seem to give me the best results with the least investment in time and trouble. Other watchmakers may do it differently.

Railroad pocket watches are done in six positions because of the multiplicity of adjustments that can be made, and usually can be made to be very consistant.

COSC calibrations are done in five positions, three temperatures, and fifteen days, and must meet a strict set of criteria. They're beyond my meager talents, but are worth researching if you are interested in such things.

Yes, a watch that is running +4.7 seconds a day could be tweaked to be +-0, but that will only be at one temperature, position, and power condition. Also remember that arm movement will also effect the balance wheel amplitude silghtly every time you move, so it's impossible to correlate machine based regulation with every-day use with 100% certainty.

Enjoy!
 

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Discussion Starter · #6 ·
Thanks for the excellent explanations, guys! Don't get me wrong, I'd be very happy with +4.7s, but my concern is that real-life timekeeping won't be that good. Like I mentioned earlier, when Swatch returned my watch, they said it was about +7-8 sec/day, but on my wrist and on the desktop, it was more like +11-13. I tried resting the watch in mutliple positions, and this was the best I could do. On my wrist, it was about the same. Hopefully things work out well this time!
 

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Most watchmakers will use electronic timing machines which essentially report an average rate. Having a watch adjusted in positions can be time consuming but this process strives to achieve the greatest accuracy the watch is capable of.

As mentioned the persuit of accurate timekeeping is one that can drive you nutty even with the benefit of modern equipment. But it's true, temp, mainspring, wear habits etc all have their effect which even a timing machine cannot factor in.

One thing though, I was taught that ideally watches (lever escapement)should be set to +10 s/p/d. This is to compensate for their inherent mechanical losses.
 

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The nature of mechanics and physics mean that each part in a watch will perform its job correctly within a certain margin of error. Some of this is the mechanical tolerances, and some of it is the effect of unavoidable environmental factors (like temperature). Which means that even if you were able to regulate a watch to +0 in all positions, you'd still find that the accuracy drifting +/-.

You'll find that some movements are sold in different "grades". This grade reflects the design of the movement and the tolerances that the pieces are manufactured to. In theory, this will give the watch a smaller overall margin of error, and allow the watch to be regulated to a smaller number. But for a normal grade watch, it really isn't worth getting the rate closer then +/-5 seconds; the rate at any given instance will still be all over the place.
 

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Discussion Starter · #9 · (Edited)
Well, my watch came back with a couple small printouts with results and statistics. Can someone explain what they mean?



Why is the "X +04.1 270o" circled? That's what the person from the shop told me represented the accuracy of the watch (not 4.7 like I initially thought), without mentioning position. Do the different letter combinations refer to the positions fo the watch? If so, what do they stand for (D, X, Xh, etc.)? What about the degrees posted after that (022, 270...)?

The symbols in front of the numbers on the left column look like positions of the crown (dial up, crown down, 12:00 down), but I'm not sure how to interpret the numbers after that. Any ideas? thanks a lot!

Edit: I wound the watch fully when I got it and set it dial-up. 11 hours later, it's +5 sec. At the rate it's going, that's really no better than when I sent it in, >10 sec/24 hrs. I'm going to time in several positions as well as worn on my wrist and see where it stands. I understand there will be some variation between the watchmaker's timing machine and real-life accuracy, but it's a little frustrating that they are consistently underestimating how fast this watch is.
 

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It appears that your watch was measured on a Witschi Chronoscope M1.

The columns on the left are the measurements taken. It shows the three positions that readings were taken. From left to right: Dial Position, Rate, Amplitude, Beat Error

The info on the right side is:

D maximal difference between the several test positions
XH average over horizontal test positions
X average over all test positions
DVH difference between vertical and horizontal average values
Xv average over vertical test positions
DV maximal difference between the vertical test positions

These readings look good. Why don't you set it, and wear it for a week or two? Hope you don't work in a magnet factory.:)

Steve
 
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