Automatic Watches Accuracy 

When talking about watches, we often mention accuracy – which is actually a difficult concept. The real question is: are automatic watches are accurate? How can we improve their performance? 

So, if you’re asking yourself this question, you’re in the right place to find a good answer.

Are automatic watches accurate?

The answer is yes: automatic watches are accurate, just as manually wound mechanical watches are accurate. Basically, the degree of accuracy of a watch depends on many factors, including the degree of winding of its mainspring. So, if you wear an automatic watch regularly on the wrist, the watch will tends to have a consistent degree of accuracy. This happens because its mechanism turns on with the movement of the wrist; thus, always remains active when one wears it. 

But as mentioned, this is but one of countless elements that combine to determine the accuracy of a watch.  Accuracy includes a thousand other variables, such as temperature, magnetism, and even the location in which the watch is operating.

Download an extract of The Watch Manual here

What is acceptable accuracy for an automatic watch?

Actually, the accuracy of a watch does not depend on whether it is automatic or hand-wound; it depends on the movement that it mounts, and how one adjusts the movement. Because each watch caliber behaves differently, and this depends on the accuracy of its manufacture, but also on its adjustment.

And there’s more: the same type of caliber can have very different performance. Just to give an example, the ETA 2824 caliber, which equips so many watches produced in the last 40 years, is available in four different versions: standard, elaboré, top and chronometer. And apart from the decorations and some internal elements, what changes is precisely the degree of regulation of its performance. The first is adjusted in two positions and has a performance of +/-12 seconds per day, up to +/-30; the second in three positions and has a performance of +/-7 seconds per day, up to +/-20; the third in five positions and has a performance of +/-4 seconds per day, up to +/-15; the last in six positions and has a COSC level performance -4/+6 seconds per day.

This means that the performance of a watch, automatic or manual, depends also on the skill of the watchmaker’s adjustments.

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Do automatic watches get more accurate over time?

There is a kind of urban legend circulating among watch enthusiasts, that watches need some kind of break-in to be in full working order. Probably once upon a time, when clocks were mostly handcrafted, running a watch stabilized its performance.

Today, when calibres are produced industrially in thousands of pieces, it’s not that true. Especially with some of these, like Swatch‘s Calibre 51, which are laser-adjusted. And also, we need to remember that the calibers that leave the factory already meet certain standards.

How do I make my automatic watch more accurate?

Again, what we said above gives us the key to the answer; apart from certain internal details, the various grades of gauges differ only in the adjustment we made. This means that, through careful adjustment, a good movement can achieve exceptional performance; just as you can transform a “stock” car into a road racer through the intervention of a professional.

In the case of watches, this professional is your trusted watchmaker, who knows how to get the best out of the movement in front of him. Then, after careful service, he can adjust it to perfection so that it achieves the best performance allowed by its technical specifications and construction elements.

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Is it normal for an automatic watch to lose time?

Yes, don’t worry. It’s perfectly normal for an automatic watch to perform differently once worn, and more importantly, under different conditions of use. And actually, it’s easily understandable why. An automatic watch is a small mechanical machine that works by the push of a spring and the harmonic oscillation of a wheel on itself. It has minimal tolerances in its building blocks – which are small and numerous. 

It’s made of metal, and to work well you need to disassemble and thoroughly oil it every five years (don’t do it on your own). Think of the effect of a sudden heat surge on those pieces of metal, which are known to expand with heat, and become more flexible. Then think of the tiny coil spring that regulates the oscillation of the balance, made of a very thin sheet of special metal alloy. Finally, think about the shocks that stress this little machine every day.

If you put your mind to it and consider all of these elements, you will be amazed at how reliable it can be, not how not!

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How much time does an automatic watch lose per day?

As we said before, every movement has a certain tolerance regarding its accuracy, according to thresholds established by the manufacturer. Generally, cheaper movements have greater tolerance but, in the history of watchmaking, it happened that some companies produced cheap movements with chronometric characteristics.

In addition, experience suggests that in most cases, a watch tends to anticipate rather than lose. This happens for a number of different reasons, the most common of which are the need for full service. The so-called “metal fatigue” of the mainspring, requires to replace the mainspring after a period of time; magnetization, tends to affect the thin coils of the watch’s hairspring.

Finally, you will notice that the same watch has different behaviors regarding its time keeping when you wear it from when you keep it leaning on a surface. This is the reason why we were talking earlier about “adjustment in X positions”, where the positions are just the direction in which the watch is operating (for example, leaning on a plane, leaning shear, and so on).

Is it normal for an automatic watch to run fast?

As already said, a mechanical watch, whether manual or automatic, tends to gain time rather than lose it, especially over the years. Since watches are small mechanical devices handcrafted, there’s always the chance that a watch lose or gain time.

If the timekeeping error is beyond the tolerances provided by the manufacturer, you should ask to a competent professional to examine it. After cleaning and oiling it and verifying that there are no mechanical problems, the watchmakers measure the performance of the movement; then they adjust it so that it is as accurate as possible under its most frequent conditions of use. 

Remember that if you are not an expert in watchmaking, it is absolutely not advisable to open a watch to make these adjustments. Doing this, you would compromise the warranty if the watch is new; or, in any case you would expose to possible contamination an environment that should be totally clean. As we have already explained, you must always remember that watches are small mechanical machines that work with extremely tight tolerances of tens, when not hundreds, of small elements, that work in synergy with each other.

At a glance

An automatic watch is a great solution that combines the practicality of a virtually perpetual winding mechanism, with the class and style of a mechanical watch. Moreover, most automatic watches are very accurate and long-lasting.  

A curiosity: diver watches are almost all automatic. This is because they need to avoid as much as possible the movement of the crown to wind them, which would be a problem for their water resistance.

All the images com from web

2 replies
  1. Larry Taddei
    Larry Taddei says:

    Thanks for the article I enjoyed it. I have purchase two chronometers, both new, from reputable gray market dealers. Same brand. They have both come off the shelf not running to the chronometer spec, at approximately 8-9 seconds fast per day. Is that common? Thanks.

    Reply
    • Franz
      Franz says:

      Indeed, chronometers should run on COSC limits – that is -4/+6 seconds per day. So yours are a bit off the mark. i suggest a revision – they might be older watches which have been sleeping a bit too long in the vault.

      Reply

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