How accurate is your COSC watch really
Discussion
I have 2 mechanical watches I wear regularly:
My Longines zulu time seems to gain 1-2 seconds a day.
My JLC Polaris (they have their own standards) is about the same.
My various ‘cheaper’ Seiko, glycine etc are significantly worse but intend to only wear them occasionally. The Casios and other random battery things are within a few seconds a month except one swatch which seems to prefer to run at random speeds.
My Garmin is, of course, always spot on, as is my Apple Watch.
My Longines zulu time seems to gain 1-2 seconds a day.
My JLC Polaris (they have their own standards) is about the same.
My various ‘cheaper’ Seiko, glycine etc are significantly worse but intend to only wear them occasionally. The Casios and other random battery things are within a few seconds a month except one swatch which seems to prefer to run at random speeds.
My Garmin is, of course, always spot on, as is my Apple Watch.
gt40steve said:
That sounds a mistake ?
ISO / COSC chronometer accuracy must be within +6 to -4 seconds a day as I understand it.
Several manufacturers are approved to test & certify in house, so no, not every watch goes to Switzerland for calibration.
My Bremont was well within this specification for several years. It eventually started gaining, mainly due to magnetism (it's not one of the Faraday caged movements).
Since I returned it to the factory for a service, it is back to 'as new' accuracy. Stripped, cleaned, demagnetised, reassembled, tested, regulated and certified again with a two year guarantee. (£375 FYI)
I've recently had a visit to the factory & saw the service department, new builds, and testing process first hand. Interesting, fiddly stuff !
Wish my bill was £375. I think you can mulitply that by 8 and you'd still have to find some change down the back of the sofa ISO / COSC chronometer accuracy must be within +6 to -4 seconds a day as I understand it.
Several manufacturers are approved to test & certify in house, so no, not every watch goes to Switzerland for calibration.
My Bremont was well within this specification for several years. It eventually started gaining, mainly due to magnetism (it's not one of the Faraday caged movements).
Since I returned it to the factory for a service, it is back to 'as new' accuracy. Stripped, cleaned, demagnetised, reassembled, tested, regulated and certified again with a two year guarantee. (£375 FYI)
I've recently had a visit to the factory & saw the service department, new builds, and testing process first hand. Interesting, fiddly stuff !
Not really worth it watch wise, mainly sentimental value
On an entirely different note, I found a Casio F91-W on a beach in south wales about 20 years ago. I wore it on and off for a while, purely for the novelty value. After about five years of using it occasionally when I knew I’d be getting wet or dirty, the strap broke and the display started fading. I bought a new strap from Casio, put a new battery in it after which, it went in a drawer.
I was rummaging in the drawer at the weekend and remembered the watch - it had lost under two minutes in the last 15 years…
I was rummaging in the drawer at the weekend and remembered the watch - it had lost under two minutes in the last 15 years…
pistonheadforum said:
Genuine question and interested in the spread of numbers for folk who wear a COSC watch on a daily basis.
If you can set it for a single day and find out how fast/slow it's running it would help as trying to build a database of manufacturers/models with real world performance.
Thanks in advance.
My Sky Dweller loses 2 seconds a day. But if I leave it dial up overnight, it comes back to a zero loss and spot on.If you can set it for a single day and find out how fast/slow it's running it would help as trying to build a database of manufacturers/models with real world performance.
Thanks in advance.
My GP, when first worn is about 1 second a day fast.
I hate to be 'that guy' but isn't this a bit pointless as you don't know the condition and use of all these watches you are asking about.
How old is the watch?
Has it been serviced?
Has it been served by an approved service centre?
How long ago was it serviced?
Has it been dropped or otherwise had the movement 'knocked'?
Is it being wound correctly, and wound enough, on a regular basis?
How is it being worn and does that affect the timekeeping?
Is it perhaps suffering from any kind of magnetism?
There are far too many variables to get any meaningful data.
I've know people who own newish COSC watches with terrible timekeeping, and I've owned old bangers of ETA powered automatics which haven't been serviced for nearly a decade, which run within about 10 seconds a week.
How old is the watch?
Has it been serviced?
Has it been served by an approved service centre?
How long ago was it serviced?
Has it been dropped or otherwise had the movement 'knocked'?
Is it being wound correctly, and wound enough, on a regular basis?
How is it being worn and does that affect the timekeeping?
Is it perhaps suffering from any kind of magnetism?
There are far too many variables to get any meaningful data.
I've know people who own newish COSC watches with terrible timekeeping, and I've owned old bangers of ETA powered automatics which haven't been serviced for nearly a decade, which run within about 10 seconds a week.
Lord Marylebone said:
I hate to be 'that guy' but isn't this a bit pointless as you don't know the condition and use of all these watches you are asking about.
How old is the watch?
Has it been serviced?
Has it been served by an approved service centre?
How long ago was it serviced?
Has it been dropped or otherwise had the movement 'knocked'?
Is it being wound correctly, and wound enough, on a regular basis?
How is it being worn and does that affect the timekeeping?
Is it perhaps suffering from any kind of magnetism?
There are far too many variables to get any meaningful data.
I've know people who own newish COSC watches with terrible timekeeping, and I've owned old bangers of ETA powered automatics which haven't been serviced for nearly a decade, which run within about 10 seconds a week.
How old is the watch?
Has it been serviced?
Has it been served by an approved service centre?
How long ago was it serviced?
Has it been dropped or otherwise had the movement 'knocked'?
Is it being wound correctly, and wound enough, on a regular basis?
How is it being worn and does that affect the timekeeping?
Is it perhaps suffering from any kind of magnetism?
There are far too many variables to get any meaningful data.
I've know people who own newish COSC watches with terrible timekeeping, and I've owned old bangers of ETA powered automatics which haven't been serviced for nearly a decade, which run within about 10 seconds a week.
Indeed - completely pointless but somewhat interesting hopefully. I had always assumed that COSC meant spot on but now appreciate the whole "dial up" shenanigans overnight to bring it back inline and think that adds to the charm of a mechanical watch.
Beer has been paid in full, but interesting to hear that most people are getting COSC bang-for-buck unless they have a bigger problem with their watches.
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