Cosc Question

[azwatchman]

Hell friends,

 

I have recently purchased a Tudor North Flag. It is COSC certified. On my time grapher it runs from -6 to -2 in the six different positions. That is a total of 4 seconds a day

total variation if I am correct. I get a 2 ms beat error. So, my question is this, is this an acceptable range and just a speed error or should I take it in and have it adjusted?

 

Thank you and I look forward to your opinions.

 

P.S. This is my first COSC watch. I mostly have Steinhart's.

[oldhippy]

I would leave it. Who is to say your time grapher just might not be calibrated to such a high standard. COSC certified is more refined to a bog standard timing machine which most watch makers/ repairers have in their workshop

[clockboy]

If the beat error is 2ms not 0.2ms then it is out of an acceptable range. The acceptable range is 0.4 ms or lower. Although the watch will run without adjustment.

[azwatchman]

If the beat error is 2ms not 0.2ms then it is out of an acceptable range. The acceptable range is 0.4 ms or lower. Although the watch will run without adjustment.

[oldhippy]

I found this for you.

 

What's Minus4Plus6.com

The name Minus 4 PLUS 6 is derived from the Contrôle Officiel Suisse des Chronomtres (COSC) standard deviation rate of -4 to +6 seconds within a 24 hour day, tested over a ten day period of chronometer testing, in five positions and at three temperatures. Watches that are within -4 to +6 seconds deviation in a 24 hour period are awarded Official Chronometer Certification by COSC and the movement is engraved with a chronometer serial number. Rolex has a self-imposed stricter standard of -1 to +5 seconds per day and hence the designation, "Superlative Chronometer Officially Certified" on the dial of any COSC certified Rolex watch.

With 86,400 seconds in a 24 hour period (31,536,000 sec/year), a difference of +3 seconds per day is a deviation of 0.000035 (thirty five millionths) of a 24 hour run resulting in 99.99% accuracy. A Rolex watch balance oscillates at a frequency of 28,800 times per hour, - equivalent to a car going 87 mph, and traveling a distance of 3,600 miles a year.

[azwatchman]

I'm sorry. Yes .2 ms. I love this watch.

[azwatchman]

I found this for you.

What's Minus4Plus6.com

The name Minus 4 PLUS 6 is derived from the Contrôle Officiel Suisse des Chronomtres (COSC) standard deviation rate of -4 to +6 seconds within a 24 hour day, tested over a ten day period of chronometer testing, in five positions and at three temperatures. Watches that are within -4 to +6 seconds deviation in a 24 hour period are awarded Official Chronometer Certification by COSC and the movement is engraved with a chronometer serial number. Rolex has a self-imposed stricter standard of -1 to +5 seconds per day and hence the designation, "Superlative Chronometer Officially Certified" on the dial of any COSC certified Rolex watch.

With 86,400 seconds in a 24 hour period (31,536,000 sec/year), a difference of +3 seconds per day is a deviation of 0.000035 (thirty five millionths) of a 24 hour run resulting in 99.99% accuracy. A Rolex watch balance oscillates at a frequency of 28,800 times per hour, - equivalent to a car going 87 mph, and traveling a distance of 3,600 miles a year.

[azwatchman]

I found this for you.

What's Minus4Plus6.com

The name Minus 4 PLUS 6 is derived from the Contrôle Officiel Suisse des Chronomtres (COSC) standard deviation rate of -4 to +6 seconds within a 24 hour day, tested over a ten day period of chronometer testing, in five positions and at three temperatures. Watches that are within -4 to +6 seconds deviation in a 24 hour period are awarded Official Chronometer Certification by COSC and the movement is engraved with a chronometer serial number. Rolex has a self-imposed stricter standard of -1 to +5 seconds per day and hence the designation, "Superlative Chronometer Officially Certified" on the dial of any COSC certified Rolex watch.

With 86,400 seconds in a 24 hour period (31,536,000 sec/year), a difference of +3 seconds per day is a deviation of 0.000035 (thirty five millionths) of a 24 hour run resulting in 99.99% accuracy. A Rolex watch balance oscillates at a frequency of 28,800 times per hour, - equivalent to a car going 87 mph, and traveling a distance of 3,600 miles a year.

[azwatchman]

Thank you. When put like that the watch is working great.

[transporter]

4 seconds a day....... I mean are you REALLY going to notice this.

[azwatchman]

No I won't. I was just trying to find out if my Tudor was in the right place.

[Ishima]

I forget what the official chronometer tolerance is, and google isn't being helpful, am I right in saying it's -5/+5 seconds in 24 hours? 

Anyway to answer the question, -4s is very accurate, chronometers can be more accurate than that but in reality the margin is totally unnoticeable in actual practicality,  and no mechanical watch, Chronometer or otherwise will ever be perfect. I don't personally see this as being worth adjusting. 

Edited February 27, 2016 by Ishima

[azwatchman]

-4 and +6

[ramrod]

did i read somewhere that since seiko wasn't allowed to play in the swiss chronometer games, they took their marbles and went home - only to make tougher standards for their certified watches?

[bobm12]

 

No I won't. I was just trying to find out if my Tudor was in the right place.           

No, sir, not in the right place, you need to send it to my home address...then it will be in the right place! :D

 

I love Tudors too!! It's a great watch, just use it and enjoy it!

 

Cheers,

 

Bob

[azwatchman]

Thanks Bob. I will.