Quote:
Originally Posted by Luis D
Rolexes are COSC-certified chronometers, which means they are adjusted to run consistently in 5 positions (crown up, crown down, crown left, crown right, dial up), and a proper overhaul entails adjusting them to the COSC standard once again.
|
Luis--"Adjusted to run consistently in 5 positions" is accurate but ambiguous as you stated it. It's worth checking the encyclopedia about chronometer certification. It may have changed since I gave the matter some study thirty years ago, but basically:
The manufacturer delivers a box of watches (9 or 12 or 16, some standard and specified number) to the certification agency.
The certification agency chooses a single watch from that batch and puts it through a set of positions--so many minutes on its face, so many on its side etc. If at the end of the test period the watch has not gained or lost any time, then *all* the watches in the box are declared Certified Chronometers.
If on the other hand the watch fails the certification test, then all the remaining watches in the box are individually tested. In this case, those that pass receive certification and those that fail are returned uncertified to the manufacturer to do with as he will. For example, he could simply sell these without the chronometer designation; or he might recalibrate them for resubmission; or he might even salt the failed watches into future batches offered for certification.
Remember, the agency that certifies chronometers is part of and both funded and accredited by the Swiss watch industry. There are, I think, only two brands that make wide use of chronometer certification as a selling point. At one time, Rolex advertising said that more than half of all certified chronometers were Rolexes. At the same time, an Omega brochure claimed that Omegas were such good timekeepers that nearly half of all watches certified as chronometers were Omegas.
Note also that certifying a watch as a chronometer requires putting it into a specified series of positions and afterward verifying timekeeping. Chronometer certification does not make any claims about maintaining time in each position, but rather that the watch gains and loses expected amounts of time in each position so that the overall result is no gain or loss.
This information comes from memory, and I'm sure I'm off in some details (such as how many watches are submitted for certification at a time). But there's a lot to be learned about how the Swiss watch industry works, and it's worth a bit of study. It's really fascinating.