"superlative chronometer officially certified"
Discussion
Each officially certified COSC chronometer is identified by a serial number engraved on its movement and a certification number given by the COSC.
Testing criteria are based on ISO 3159[9] which defines a wrist chronometer with spring-balance oscillator. Only movements which meet the precision criteria established under ISO 3159 are granted an official chronometer certificate. Compare ISO 3158.[10]
Each uncased movement is individually tested for fifteen days, in five positions, at three different temperatures. The movements are fitted with a seconds hand and the automatic winding mechanisms are disengaged for the tests. Measurements are made daily with the aid of cameras. Based on these measurements, seven eliminatory criteria are calculated, each of which must be met e.g. for movements of a diameter over 20 mm, the requirements, indicated in seconds/day, are noted in the table below. There is no ISO standard for quartz timepieces, but there is develpment in this field. ISO 10553:2003 specifies the procedure for evaluating the accuracy of quartz watches, individually and by lot, and the relationship between the accuracy tested and the accuracy classification given by the manufacturer. It applies to quartz watches having accompanying documents on which the accuracy classification is indicated. Nevertheless, COSC has also developed its own standard for testing quartz chronometers with eight eliminatory criteria, also noted in the table below.
COSC Standards Mechanical Quartz
Measurements are compared with a time base established by two independent atomic clocks synchronized on GPS time. Not all chronometers are supplied with the report issued by the COSC as the reports are optional to the brand or maker. Each manufacturer may decide whether to reveal the results gathered during the certification process of the movement. For example, Rolex and Omega do not supply their chronometer certified watches with the COSC certificates. However, Omega can provide the COSC chronometer certificate if asked.
THANK YOU WIKI>
briano
Testing criteria are based on ISO 3159[9] which defines a wrist chronometer with spring-balance oscillator. Only movements which meet the precision criteria established under ISO 3159 are granted an official chronometer certificate. Compare ISO 3158.[10]
Each uncased movement is individually tested for fifteen days, in five positions, at three different temperatures. The movements are fitted with a seconds hand and the automatic winding mechanisms are disengaged for the tests. Measurements are made daily with the aid of cameras. Based on these measurements, seven eliminatory criteria are calculated, each of which must be met e.g. for movements of a diameter over 20 mm, the requirements, indicated in seconds/day, are noted in the table below. There is no ISO standard for quartz timepieces, but there is develpment in this field. ISO 10553:2003 specifies the procedure for evaluating the accuracy of quartz watches, individually and by lot, and the relationship between the accuracy tested and the accuracy classification given by the manufacturer. It applies to quartz watches having accompanying documents on which the accuracy classification is indicated. Nevertheless, COSC has also developed its own standard for testing quartz chronometers with eight eliminatory criteria, also noted in the table below.
COSC Standards Mechanical Quartz
- Average daily rate: -4/+6 [11] * Average daily rate at 23 °C: ± 0.07
- Mean variation in rates: 2 [12] * Rate at 8 °C: ± 0.2
- Greatest variation in rates: 5 [13] * Rate at 38 °C: ± 0.2
- Difference between rates in H & V positions: -6/+8 [14] * Rate stability: 0.05
- Largest variation in rates: 10 [15] * Dynamic rate: ± 0.05
- Thermal variation: ± 0.6 [16] * Temporary effect of mechanical shocks: ± 0.05
- Rate resumption: ± 5 [17] * * Rate resumption: ± 0.05
- n/a * Residual effect of mechanical shocks: ± 0.05;
Measurements are compared with a time base established by two independent atomic clocks synchronized on GPS time. Not all chronometers are supplied with the report issued by the COSC as the reports are optional to the brand or maker. Each manufacturer may decide whether to reveal the results gathered during the certification process of the movement. For example, Rolex and Omega do not supply their chronometer certified watches with the COSC certificates. However, Omega can provide the COSC chronometer certificate if asked.
THANK YOU WIKI>
briano
The word "superlative" is Rolex.
Perhaps you're confused between chronograph (a watch with a stopwatch function) and a chronometer.
Dr JonboyG said:
Peter G said:
The superlative is a bit of Rolex marketing I believe.
A watch is either a chronometer, or its not.
How can it be Rolex marketing if my Breitling is COSC certified?A watch is either a chronometer, or its not.
Perhaps you're confused between chronograph (a watch with a stopwatch function) and a chronometer.
Dr JonboyG said:
Peter G said:
The superlative is a bit of Rolex marketing I believe.
A watch is either a chronometer, or its not.
How can it be Rolex marketing if my Breitling is COSC certified?A watch is either a chronometer, or its not.
Perhaps you're confused between chronograph (a watch with a stopwatch function) and a chronometer.
As x200sxy says above, its the "superlative" label thats Rolex added.
Off topic, every Breitling movement is COSC certified according to the bumpf that came with mine, they claim to be the only 'volume' manufacturer to submit its entire movement production for COSC cert.
Edited by Peter G on Thursday 23 April 18:13
Moreover a watch can perform to chronometer standard without actually being certified as such. And many do - my Sinn for example (now owned by Stuart) was within 1 second of my time-synch'd laptop over 7 days.
JLC for example don't submit any of their watches to the COSC but their own 1,000 hours test is more rigorous and applies to the whole watch (ie in the case) not to the uncased movement, which is how the COSC certification is done.
Overall I reckon its mainly marketing.
And the superlative bit is just
less is more and all that ...
JLC for example don't submit any of their watches to the COSC but their own 1,000 hours test is more rigorous and applies to the whole watch (ie in the case) not to the uncased movement, which is how the COSC certification is done.
Overall I reckon its mainly marketing.
And the superlative bit is just
less is more and all that ...Gassing Station | Watches | Top of Page | What's New | My Stuff