Horological Meandering

Hello to all PuristS,

I have been reading this site for at least two years without registering.

This is my first post because I really need your opinion on something I find rather strange.
So, here it goes: I have a small collection of watches and that I wear them all on a regular basis. Last Christmas I finally purchased a 6-head winder, set all my automatic watches precisely, set the correct winding direction for all of them and pressed the On button.
Now, after almost two month spent without any adjustment, most watches are off by some margin but the strange thing is that, contrary to what I expected, the ones with official chronometer certifications fared no better than the others. Actually, the worst offender (~12 minutes FAST in 50 days) is a watch that has only "-" (minus) figures on the COSC certificate, meaning - if my understanding is correct - that it should run SLOW under any circumstances.
Just for fun (although I don't feel like laughing, since officially certified chronometers tend to cost more than "regular" watches using the same movement), the most precise watches are a Sinn 144 chronograph "Lufthansa Cargo" with a deviation of less than 30 sec. and a... Swatch Irony (which is... ironical, if you'll excuse my pun).

Now am I missing something or what?

Thank in advance for any light you can shed on the matter.

added to Editor's Pick

This message has been edited by AnthonyTsai on 2008-02-18 19:10:53

A chronometer certificate is usually not worth much in terms of practical performance. It may add prestige value but little more. One reason is that COSC tests are done on movements before they are cased, during the later process of adding the dial and hands and casing the movement a lot can happen.

- SJX

Welcome to the world of a poster rather than a lurker ! That wasn't so painful was it?

Next, a slap on the wrist for taking 2 years to lose your posting virginity  -  is that a PuristS' record?

That is why the more stringent tests at 'Qualite Fleurier' and Besancon that study the whole watch and even the real hands may be the way to go......

Regards, MTF

...but you'll have to wait until I take off the mega-complicated extremely limited edition five-year waiting list watch that I'm just wearing (brand and model witheld for personal security reasons). You know those flying tourbillons are not as shock-proof as they should be (and those tiny chimes get out of tune so easily) 

Regards, pisoi 

In my experience, if you don't like the way your watch keeps time and complain to the manufacturer, you stand an excellent chance of being told that the watch is "within specification" and the manufacturer will not correct it. If your watch has a chronometer certificate and is not keeping time within chronometer standards, it is much harder for the manufacturer to take that approach.

You do have to have some sensitivity to condition. A watch that is keeping very poor time is probably damaged, magnetized or in need of service. (15 seconds/day fast is very poor time for a chronometer or high-end modern watch; for older or lower-end watches, it may be acceptable. If the timekeeping is consistent, it can be regulated easily.)

Maybe I'm just lucky, but the certified chronometers I have owned have all kept excellent time. Only occasionally do I get comparably good results from a non-certified watch, even if it is very high-end.

The worst offender is a Sinn 244 Ti. The watch is ~6 month old and touted to be extremely resistant to magnetic fields (inner case of soft iron) up to 80,000 A/m.

The movement is an ETA 2892-A2 (nothing to write home about).

Now (and this is a reply to MTF) this is more or less the league I'm playing in - my most expensive watches are a GP9000 chronograph (purchased pre-owned in 1995) and an Omega DeVille Coaxial Escapement in RG (first coax launched, "limited edition" - mine is 995/999). So, I hope you understand why I was somewhat reluctant to register on a forum where I read that the finish on some five-digits (USD) PP movement is "average".  

Regards,

pisoi

Hi

Just thought I will share with you some remarks on accuracy and consistency of watch performance ( I came across this in FPJourne catalog on the subjet of chronometry).

Typically a chronometer certification certifies the deviation of the watch in various positions and temperature changes. Once it leaves say Geneva ( as typical swiss... watches ), the watch would be subject to a different gravitational pull by virtue of its new location ( say in Singapore versus Geneva) and this affects the timing. The next will be the temperature which has a significant bearing on the deviation.

Thus if a  watch gains 5 seconds per day in Singapore compared to  being 1 second slow in Geneva ( when it left after chronometer certification), all it needs to exhibit as a behaviour is to gain the same 5 seconds each day without erratic deviations. The watch can be certified as Accurate.

Thus it is not the deviation but the consistency of the rate of change or deviation that determines if a watch can be termed to be running accurately.

 

Regards

 

narsi

 

 

 

Since it means these watches are certified as being accurate and therefore can be set to run properly (within limits) using the rate regulation mechanisms found in all of them.

Thanks

Hi

 

Yes. It can be adjusted. One important aspect I failed to mention is that when the lubricants in the watch deteriorate, the watch will GAIN time. Most of us would assume the opposite.

 

Regds

narsi

 

 

Hi Narsi,

I'm a bit confused about some of the points in the info you quote.  For example, I'm not at all sure that variations in gravity are a major, or even a minor, concern for wristwatches.  Given that movements like the Lemania 5100 are known to be able to pull many Gs, and that watches have been worn into space with no apparent timing problems, I don't see how it can be that much of a factor.  Gravity certainly is a problems for ultra-precision clocks, but we're talking of fractions of a seconds per year, not seconds per day, and it's due to a very specific effect - the pendulum rod being microscopically lengthened or shortened by changes in gravity.  The key point in clocks is that as they never move, and as the pendulum is pulled on by gravity, there's a very definite connection between the change in gravity and change in rate.  In a watch that's being worn, and hence moving all the time, I don't see an analagous constant physical change that would cause a different, stable rate.

I wonder if there are translation problems.  The sentence "Typically a chronometer certification certifies the deviation of the watch in various positions and temperature changes. " doesn't make sense to me.  The certificate gives absolute figures and average (mean) figures, and it rates these against a standard, so I don't know how "deviation" comes into it.

Similarly, the sentence "Thus it is not the deviation but the consistency of the rate of change or deviation that determines if a watch can be termed to be running accurately." strikes me as odd.  Consistency of rate of change of what?   You normally talk of rate of change of daily rate or similar, but I realy don't understand it in this context.

I think the final sentence is trying to say something like "The absolute rate is not important, but it's the consistency of the rate that determines if a watch can be said to be running accurately", and I'd have no problem with this statement.

Sorry to be nit-picking, but I found it very confusing.

nick

The chronometer testing involves several tests, but its most important part can be summarized as requiring that the variation between the watch's fastest and slowest position (and in different temperatures) is not more than 10 seconds/day. It also requires that the variation take place within the range -4 to +6. If you have a watch with low variation that is running at the wrong speed that can be regulated; if you have a watch with high variation, that is much harder to correct.