did not sell? a bit like buying a diesel Maserati...
How does someone even become an "Independent Expert" on watch authenticity? Specifically Rolex
- Thread starter JT20
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Cars also have lots of initial problems, not a huge fan of JD powers, but one can get an idea of issues that are missed.
Are you talking about Rolex's testing post cosc movement test? How long is it?
I think the pressure test is the big one for getting the cert and of course the +4 -2 min a day.
I'm struggling to think of how casing changes the timing of a watch short of physically damaging the movement in the casing process. Any damage of that sort that would affect the timing would show up in 10 seconds on a timing machine.
Because expansion and contraction is different for the case than the internal movement and can take way longer than 10 seconds.
Why does JLC bother with a 1000 hour test all cased up vs. just movements?
I'm asking this respectfully and not argumentatively, but do understand why and how of the effect of temperature on the timekeeping of a mechanical movement?
Just a bunch of guys talking about watches, im not arguing an hope Im not coming across that way.
Because tolerances grow and shrink differently for different metals while being subjected to vibration and positioning changes.
I'm not trying to argue either, but at the same time I have spent a lot of time studying this stuff and putting into practice, so in a sense I'm challenging your statement.
Here's my "long answer" as to why, and I know some of this stuff is basic information, but bear with me.
A typical watch movement has 5 gears in constant mesh, or "wheels" in watch parlance. Although not often called a "wheel" the first of these is the mainspring barrel, which of course carries the torque of the unwinding mainspring.
This meshes with a wheel traditionally called the center wheel. Historically, the center wheel was quite literally in the geometric center of the movement, and directly drove the minute hand. Consequently, it makes one complete rotation once per hour.
Moving on down the train, you have the 3rd wheel, which has no fixed rotational speed, and then the 4th wheel, or sometimes called the "seconds wheel". Again, this traditionally drove the second hand directly, and consequently rotated once per minute. There again, from the center wheel to 4th wheel, there is a 1:60 increase in rotational speed.
Meshing with the 4th wheel is the escape wheel. This wheel, in combination with the pallet fork(in a lever escapement watch, which is most everything now outside the Omega Coaxial), both stops and starts the train, and also transmits power from the train to the balance wheel. Typically the escape wheel has 15 teeth, and advances forward by one tooth for every oscillation of the balance. You can do the math on its rotational speed-on the 18,000 bph watches I normally work it rotates once every 3 seconds.
I go through all of this for a reason. The correct sideshake(spacing) of all of these wheels is critical on set-up, and ideally they "roll" over each other without the teeth bottoming out. None the less, though, expansion or contraction of these with temperature isn't particularly significant because rotational speeds are so low and torque is(relatively speaking) quite high.
If the escape wheel does change appreciably in size, it can affect the pallet stone engagement which does affect balance amplitude, but I quite literally have never seen that become an issue on watches of any size.
You then, by means of the pallet fork, get to the balance wheel. This is the harmonic oscillator in combination with the hairspring that is the ultimate timekeeper in the watch. The "beat rate" of a watch describes the oscillation frequency of the balance wheel-i.e. 8 times per second in a 28,800bph watch. The balance wheel, for most of its rotation(generally 220-240º in each direction-this is a design parameter of the watch and is called the amplitude) is completely free spinning. It ONLY interacts with the balance wheel through a few degrees of rotation(called the lift angle, BTW) by way of the roller jewel or impulse jewel. During this period of interaction, it "kicks" the pallet fork over, which allows the escape wheel to advance by one tooth, and as the escape wheel advance it feeds energy back into the balance wheel. This allows it to reach a steady frequency.
I've gone through all of that because, again, the oscillation frequency is key to timekeeping, and in particular having a consistent, repeatable oscillation frequency. It is the fastest spinning wheel in the watch, and as it is mostly freely spinning on just its pivots, a lot of things can affect its velocity, or more importantly the amplitude. One of the first goals is to have the balance wheel be isochronic, or have the frequency remain constant regardless of amplitude. I'm ignoring the temperature elephant in the room now, but things like varying friction across positions, a balance wheel out of poise(not balanced around its perimeter) or a lot of other things can affect amplitude, and isochronism is largely kept in check by properly formed hairsprings. Some hairspring designs are better at this than others. The helical hairspring is the gold standard for this, but it's far too thick for wristwatches, or even most pocket watches(I do know of helical spring pocket watches). It's mostly seen in things like deck watches and true chronometers. Next down the list is the overcoil hairspring, which is still used some(by Rolex in particular). Flat hairsprings are worst, but careful forming and newer tricks like the "dogleg" terminal curve are better than a plain, simple flat spring. Conventional regulators are a huge issue as well, as the interaction between the hairspring and regulator pins can be problematic. Consequently, freesprung designs, or designs without a regulator, are preferred but are more difficult to adjust the timing. Rolex almost universally uses freepsrung designs, and regulation is accomplished by tiny nuts on the balance wheel(called "Microstella nuts") that change the moment of inertia and are adjusted with a special wrench.
In any case, temperature does affect the balance wheel. The oldest watches used a carbon spring steel hairspring and a monmetallic flat balance wheel typically made of steel or gold. There are two big issues with this-thermal expansion of the balance whee and change in the spring constant of the hairpsring. At high temperatures, the wheel expands and the spring becomes less elastic, both of which slow the rate. At low temperatures, the opposite happens-the spring becomes more elastic and the wheel smaller, so the watch speeds up.
The first attempt to fix this was the split bimetallic balance wheel, which is laminated steel and brass(usually). At high temperatures, the ends of the arms curl inward decreasing the effective diameter, and at low temperatures they curl outward to increase the diameter. The idea is to counteract the change in spring elasticity. This was a complicated process that often involved moving weight around the rims(using brass or gold screws) to find the right spot, and it still left residual "middle temperature error." Adjusting a split bimetallic watch to temperature is not one of my favorite things to do.
Back in the 1930s, the Swiss developed a material called Elinvar, or short for "Elastically Invariable." As the name would suggest, the spring constant stays more-or-less the same regardless of temperature. This was used in combination in some cases with Invar, which is an alloy with a low coefficient of thermal expansion. Middle temperature error still hangs around but it can amount to a couple of seconds a week. The late George Daniels tried a few different techniques, including a few designs of bimetallic balance. He finally settled on using a set of four bimetallic "fingers" facing inward that would iron that error down to a second or so a week. That's really splitting hairs, though.
In any case, the long and the short of it is that modern mechanical watches really aren't affected by temperature, or at least normal temperatures to which they're likely subjected. IIRC, COSC does include temperature testing also. The rate of change in temperature is not going to be different enough to matter cased or uncased. In fact, the case can add enough thermal inertia that temperature swings will be less extreme and conceivably a movement COULD(not necessarily will) rate better cased than uncased. I'm having a hard time thinking of a situation where an uncased movement would rate worse than the same movement cased.
Great post.
Why would JLC, Patek, Fleurier, Geneva, and Besancon bother to test the cased watch vs. just a movement?
Heres an interesting link to testing, and who tests cased watches vs movements.
www.watchtime.com
It seems Cosc will test cased watches, I wonder why bother if there is no point?
"For an added fee, COSC can also test cased-up watches and perform a modified, manual version of the standard chronometer test. In 2012, COSC issued 1.73 million certificates; some 85 percent of those went to three brands: Rolex, Omega, and Breitling."
Why would JLC, Patek, Fleurier, Geneva, and Besancon bother to test the cased watch vs. just a movement?
Heres an interesting link to testing, and who tests cased watches vs movements.
Who Tested Your Watch? A Guide to the Watch Industry's Quality Marks
People often wonder just how good their watches are. A quality seal can help provide an answer: it shows that the watch has passed a test for its timekeeping ability and, in some instances, the quality of its finishing. COSC and the Geneva Seal are by far the best-known issuers of quality certificat
www.watchtime.com
It seems Cosc will test cased watches, I wonder why bother if there is no point?
"For an added fee, COSC can also test cased-up watches and perform a modified, manual version of the standard chronometer test. In 2012, COSC issued 1.73 million certificates; some 85 percent of those went to three brands: Rolex, Omega, and Breitling."
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It would seem Cosc will test a cased watch.
Interesting reason that seems self evident after reading it.
" Besançon tests only cased-up movements.
That’s because the Observatory believes that adding complication plates and a dial and then casing up the movement can alter the watch’s rate, making a raw-movement test ineffective.
" Besançon tests only cased-up movements.
That’s because the Observatory believes that adding complication plates and a dial and then casing up the movement can alter the watch’s rate, making a raw-movement test ineffective.
If you send a movement to COSC, it MUST havee all parts assembled. Seems to me Besancon is trying to market their services offering something alternative (but irelevant). when you encase a watch you triple check that everything stays like before
Some very interesting viewpoints here.
I wore a GMT Master daily for years, until I lost it in 2005.
Picked up a 16600 (SeaDweller) a week later, and it's been on my wrist practically every day these past 15 years. Also picked up a 118206 (DayDate) in 2005, but I don't really wear it much, a dozen times a year or so, when I absolutely know I won't be using tools or stringing barbed wire etc.
The one watch I really don't like is the Daytona my Dad gifted me for my wedding. I have worn it exactly once, as I'm just not a fan of gold faces & multiple dials.
This thread just reminded me to give the Daytona to my niece.
I wore a GMT Master daily for years, until I lost it in 2005.
Picked up a 16600 (SeaDweller) a week later, and it's been on my wrist practically every day these past 15 years. Also picked up a 118206 (DayDate) in 2005, but I don't really wear it much, a dozen times a year or so, when I absolutely know I won't be using tools or stringing barbed wire etc.
The one watch I really don't like is the Daytona my Dad gifted me for my wedding. I have worn it exactly once, as I'm just not a fan of gold faces & multiple dials.
This thread just reminded me to give the Daytona to my niece.
COSC does use "generic" dials/hands, and I could potentially the actual ones causing issues.
With that said, when I've encountered dial/hand issues affecting timing, it's essentially immediately obvious. It will be things like the dial rubbing the canon pinion and causing the minute hand to drag, or the hands clashing(easy to find if you just spin the hands around a full 12 hour cycle after you've seated them). The canon pinion issue causes errors of minutes per hour, so again it's not something that's going to creep up as a few seconds a day.
JLC's casing thing sounds a bit marketing as much as anything, and also seems to focus on pressure testing during the timing. That's something that really won't change timing any appreciable amount unless there's water ingress, but then timing is the least of your concerns.
With that said, when I've encountered dial/hand issues affecting timing, it's essentially immediately obvious. It will be things like the dial rubbing the canon pinion and causing the minute hand to drag, or the hands clashing(easy to find if you just spin the hands around a full 12 hour cycle after you've seated them). The canon pinion issue causes errors of minutes per hour, so again it's not something that's going to creep up as a few seconds a day.
JLC's casing thing sounds a bit marketing as much as anything, and also seems to focus on pressure testing during the timing. That's something that really won't change timing any appreciable amount unless there's water ingress, but then timing is the least of your concerns.
Although it seems to me that with so many dissimilar metals and masses there exist the capacity for something to change enough to be meaningful about the case vs movements especially when the mainspring is mostly unwound.
It may be that temperature differences between the movement and the case may not really effect anything much of all.
It would be interesting to learn a little more about why some chose to test cased vs uncased movements.
Id rather know the reasons behind eth choices than be "right" about was only one assumption as to why.
Too many things to learn, to little time to learn them.
Great post.
Why would JLC, Patek, Fleurier, Geneva, and Besancon bother to test the cased watch vs. just a movement?
Heres an interesting link to testing, and who tests cased watches vs movements.
Who Tested Your Watch? A Guide to the Watch Industry's Quality Marks
People often wonder just how good their watches are. A quality seal can help provide an answer: it shows that the watch has passed a test for its timekeeping ability and, in some instances, the quality of its finishing. COSC and the Geneva Seal are by far the best-known issuers of quality certificat
It seems Cosc will test cased watches, I wonder why bother if there is no point?
"For an added fee, COSC can also test cased-up watches and perform a modified, manual version of the standard chronometer test. In 2012, COSC issued 1.73 million certificates; some 85 percent of those went to three brands: Rolex, Omega, and Breitling."
Regarding to Cosc testing. I was told by someone in the banking industry who said this to me once: "You can only test so many watches in COSC, and therefore limit the production amount". In other word, even if you don't need the testing (you are just a collector, not a precision equipment user), you are using this as a gate keeper to guarantee the limit of the supply, so you can guarantee the resell value in the future, in case the manufacturer decided to suddenly make a lot of them and tank the resell value of the watches.
Interesting concept as a production limiting gate, but Rolex can always remove " superlative chronometer" from the face label and bypass Cosc, not sure who even knows enough to care.
But why? Why would a manufacturer use COSC as an excuse to limit supply when they could, you know, limit the supply the old fashion way: Just not make as many?
Patek Philippe Nautilus 5711. The most sought after steel sport watch on Earth. In the midst of a 10 year wait list and valuations that doubled and even tripled retail prices, Patek just says, "We're not going to make it anymore."
It's not COSC certified. It's super popular, even at a ridiculous (for a steel watch) price. Patek just decided they were only going to make so many every year (and then none at all). No reason needed.
I mean, I'm sure Patek has their reasons. They only produce a little more than 60,000 watches every year total. Of those, less than 25% are steel. Steel watches, despite their incredible popularity and demand in the market, just aren't Patek's focus as a watchmaker.
Maybe it's to protect the value of existing 5711s?
Maybe Patek thought that rabid demand for the 5711 detracted from their focus on precious metal watches?
Who knows, but none of it stopped Patek from limiting the number of 5711s they produced each year.