COSC: Difference between revisions

[[File:COSCLogo.jpg|thumb|right|Contrôle officiel suisse des Chronomètres]]
The '''Contrôle Officielofficiel Suissesuisse des Chronomètres''' ('''COSC'''), the Official Swiss Chronometer Testing Institute, is the institute responsible for certifying the accuracy and precision of [[Swiss watch]]es.

COSC testing generally applies to watches manufactured or assembled in [[Switzerland]].<ref name="Interview de Pierre-Yves Soguel Directeur https://forumamontres.forumactif.com">[http{{Cite web|url=https://forumamontres.forumactif.com/lest23463-interviews-f6/interview-de-pierre-yves-soguel-directeur-du-cosc-t23463.htm |title=Interview de Pierre-Yves Soguel Directeur du COSC<!-- Bot generated title -->].|website=forumamontres.forumactif.com}}</ref> Notwithstanding, the normative standards are set by international agreement and are the same whether they are nominally labeled [[ISO]] or DIN standards. Some German, Japanese, and even non-certified Swiss movements can surpass the normative requirements. The Japanese have largely abandoned the accolade, replacing it with in-house testing to a slightly more strict standard as with, for example, the [[Grand Seiko]]. On the other hand, the Germans have set up their own testing facility in Saxony at the [[Glashütte Observatory]] <ref>http://www.chronometerwerke-glashuette.de/pdfs/Sternwarte_0609_EN.pdf?PHPSESSID=1fafdbfcf01fbc87c54d2ed4f0b2e530{{Dead link|date=June 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref>[{{Cite web|url=http://journal.hautehorlogerie.org/en/focus/fine-watchmaking-made-in-germany/deutsche-chronometer/deutsche-chronometer-4367.html |title=Deutsche Chronometer - Deutsche Chronometer - Fine watchmaking, made in Germany - Focus - Fondation de la Haute Horlogerie<!-- Bot generated title -->]|access-date=4 February 2008|archive-date=3 November 2007|archive-url=https://web.archive.org/web/20071103201329/http://journal.hautehorlogerie.org/en/focus/fine-watchmaking-made-in-germany/deutsche-chronometer/deutsche-chronometer-4367.html|url-status=dead}}</ref> where the DIN 8319 standards, which mirror the ISO standards used by COSC, are employed. At one time the French provided similar large scale testing at the [[Besançon Astronomical Observatory|Observatory at Besançon]], however, today only a very few watches are currently tested there and carry the accolade "[[Observatory chronometer|Observatory Chronometer]]".

Three laboratories now test the movements submitted by individual watch manufacturers to be granted chronometer status. They are in [[Biel/Bienne]], [[Saint-Imier/BE]] and [[Le Locle]]. The Saint-Imier and Biel laboratories are almost entirely devoted to testing [[Rolex]] movements.<ref>[http://www.timezone.com/library/wbore/wbore631733384647656250 {{WebarchiveCite web|url=https://web.archive.org/web/20070608035845/http://www.timezone.com/library/wbore/wbore631733384647656250 |datetitle=2007-06-08Homepage }} Inside COSC [1/22/03&#93124; - TimeZone<!-- Bot generated title -->]|website=www.timezone.com}}</ref> Although not all Rolex watches are chronometers, [[Breitling SA|Breitling]] has claimed that since 2000 all of its production is COSC certified. [[Omega SA|Omega]] also has much of its production certified. Thus, based upon the movements used by Rolex, Breitling, and Omega, the movement calibers that obtain most of the COSC certificates<ref>[{{Cite web|url=http://www.fhs.chswiss/eneng/news/newslatest_news.php?idhtml|title=565 The Swiss Watch IndustryFH - COSC 2006 1,300,140 Chronometers<!-- Bot generated title -->]News|website=www.fhs.swiss}}</ref> are the Rolex 3135<ref>Watch as described at [http://www.horlogerie-suisse.com/Complications/Rolex/3135.html horlogerie-suisse.com] {{Webarchive|url=https://web.archive.org/web/20070926224823/http://www.horlogerie-suisse.com/Complications/Rolex/3135.html |date=2007-09-26 }} and [http://vintagepocketwatches.net/watchprincipals/gauge_rolex_3135.htm vintagepocketwatches.net] {{Webarchive|url=https://web.archive.org/web/20070930175228/http://vintagepocketwatches.net/watchprincipals/gauge_rolex_3135.htm |date=2007-09-30 }}.</ref> (since 1988) (and variants 3155, 3175, 3185, 4130) and 2235, the [[ETA SA|ETA]] 2892A2<ref>Movement as described at [http://www.horlogerie-suisse.com/Complications/2892/2892-A2.html horlogerie-suisse.com] {{webarchive|url=https://web.archive.org/web/20070305075713/http://www.horlogerie-suisse.com/Complications/2892/2892-A2.html |date=2007-03-05 }}.</ref> (and variants) and [[Valjoux]] 7750,<ref>Movement as described at [http://www.horlogerie-suisse.com/Complications/7750/7750.html horlogerie-suisse.com] {{webarchive|url=https://web.archive.org/web/20070926224817/http://www.horlogerie-suisse.com/Complications/7750/7750.html |date=2007-09-26 }}.</ref> each of which operates at 28,800 beats per hour. Tag Heuer <ref>{{Cite web |url=http://www.tagheuer.com/int-en/watch-movement/cosc-certification |title=ArchivedCosc copyCertification &#124; TAG Heuer |access-date=2013-10-25 |archive-url=https://web.archive.org/web/20131029204428/http://www.tagheuer.com/int-en/watch-movement/cosc-certification |archive-date=2013-10-29 |url-status=dead }}</ref> and Ball watches <ref>{{Cite web | url=http://www.ballwatch.com/html5/index.php?option=com_collections&task=6&mid=151&lang=en_US |title = Welcome to BALL Watch}}</ref> both have select watches designated as chronometers which are sent to COSC for certification.

Testing criteria are based on [[ISO 3159]] (Timekeeping instruments — Wrist-chronometers with spring balance oscillator)<ref>[http://www.qualite-fleurier.ch/COSC-ISO-3159.pdf PDF file] {{Webarchive|url=https://web.archive.org/web/20070925200236/http://www.qualite-fleurier.ch/COSC-ISO-3159.pdf |date=2007-09-25 }} (of 1976 version)</ref> 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.<ref>[http://www.seiko-watch.co.jp/resource/pdf/manual/9S56_02.pdf ISO 3158] {{Webarchive|url=https://web.archive.org/web/20070925200233/http://www.seiko-watch.co.jp/resource/pdf/manual/9S56_02.pdf |date=2007-09-25 }} (PDF file).</ref>) The certificate is valid for the bare movement prior to casing, and only when freshly serviced or assembled. Pre-owned and vintage chronometers generally require a complete service in order to be restored to COSC-levels of performance.

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&nbsp;mm, the requirements, indicated in seconds/day, are noted in the table below). The testing protocol requires daily winding at precisely the same time each day. There is no ISO standard for quartz timepieces, but there is development in this field. ISO 10553:20032018 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. To acquire the COSC chronometer label, a quartz instrument must benefit from thermo-compensation and rigorous encapsulation.

! Mechanical<ref>[{{Cite web|url=https://www.cosc.swiss/en/certification/mechanical-movements|title=Mechanical COSCmovements mechanical&#124; movements]COSC|website=www.cosc.swiss}}</ref> !! Quartz<ref>[{{Cite web|url=https://www.cosc.swiss/en/certification/quartz-movements|title=Quartz COSCmovements quartz&#124; movements]COSC|website=www.cosc.swiss}}</ref>

===Only 3%fractions of Swiss Watch production are COSC certified===

There is a debate among watch enthusiasts as to whether the COSC chronometer certification for a Swiss watch is a meaningful test or a simple marketing gimmick. On the one hand, when a watch maker intends to submit a movement for COSC testing, they frequently employ additional jewelling (i.e. to the barrel) and better quality "[[Ébauche]]" parts (i.e. higher quality hairsprings, mainsprings, balance wheels; regulators, etc.) all aimed at the coveted chronometer certification.<ref>Better quality as explained [http://www.eta.ch/d/produkte/Mecaline/pdf/ETA_2824_2.pdf here] {{Webarchive|url=https://web.archive.org/web/20070710041751/http://www.eta.ch/d/Produkte/mecaline/pdf/ETA_2824_2.pdf |date=2007-07-10 }} (PDF file).</ref> "[[Ébauche]]" parts (i.e. higher quality hairsprings, mainsprings, balance wheels; regulators, etc.) all aimed at the coveted chronometer certification.<ref>Compare, Can a non-certified watch meet the precision criteria of a chronometer? No, as the components of a chronometer are of a better quality and the care granted to its assembly and its setting cannot be compared. See [http://www.cosc.ch/faq2.php?lang=en cosc.ch FAQ] {{Webarchive|url=https://web.archive.org/web/20070625024419/http://www.cosc.ch/faq2.php?lang=en |date=2007-06-25 }}.</ref> On the other hand, it is likely that most good quality movements on the market today are capable of being tweaked, and timed to fall comfortably within the benchmark -4/+6 average daily rate criteria of the COSC. However, movements so submitted to COSC are more likely to be submitted with better quality parts in order to be confident of a successful test, and as a consequence may be more likely to maintain better timekeeping rates over the service life of the time piece.<ref>{{Cite web |url=http://www.cosc.ch/faq2.php?lang=en |title=Can a non-certified watch meet the precision criteria of a chronometer? |access-date=2007-06-03 |archive-url=https://web.archive.org/web/20070625024419/http://www.cosc.ch/faq2.php?lang=en |archive-date=2007-06-25 |url-status=dead }}</ref>

Therefore, some of the ″Haute Horlogerie″ Swiss Watch Manufacturers have created on 5 June 2001, [http://www.fleurier-quality.com ″The Fleurier Quality Foundation″] (permanently closed) to establish new aesthetic and technical criteria dedicated to the certification of finished watches. Their certification meets a normative requirement for the market and the final customer to have a better definition of quality watchmaking, adapted to today's demands and technological advances. Geneva's have created along similar criteria the [[Geneva seal]].

[[Rolex SA|Rolex]] by far submits the largest number of movements to COSC followed by [[Omega SA|Omega]], Tudor, [[Breitling SA|Breitling]], [[TAGMido Heuer(watch)|Mido]] and [[PaneraiTissot]].

<ref>[http{{Cite web|url=https://www.watchtime.com/2010/09featured/who-are-switzerlands-top-chronometer-producers/ |title=Who are Switzerland’sSwitzerland's Top Chronometer Producers]?|first=Written byJoe|last=Thompson|date=12 September 2010|website=WatchTime - USA's No.1 Watch Magazine}}</ref> Rolex and Breitling submit all movements for certification, but other manufacturers only submit certain models.

====METASAdditional N001METAS "Master Chronometer" certification====

The Swiss [[Federal Institute of Metrology]] (METAS) has developed a new stricter standard METAS N001 requirements for movements and mechanical watches resistant to magnetic fields of 1.5 T (15,000 G).<ref>[{{Cite web|url=https://www.metas.ch/metas/en/home/dok/rechtliches/Zertifizierung_Uhren.html |title=Certification of mechanical watches|first=Federal isInstitute in accordance with the METAS requirements N001]of|last=Metrology|website=www.metas.ch}}</ref> Mechanical watches are put to the test during 10 test cycles which will consider in particular the resistance to magnetic fields, the precision of the rate (watch drift over 24 hours) and the water resistance of the watch. Unlike the '''ISO 3159 Timekeeping instruments — Wrist-chronometers with spring balance oscillator''' standard, it is no longer just the uncased movements that are tested, but completely assembeledassembled watches.

'''===Part A - Technical requirements'''<br>===

The first condition is that the watch must be "Swiss Made" and meet the requirements set by the ordinance regulating the use of the name “Switzerland”"Switzerland" for watches (RS 232.119), in its latest version in force. In addition, the movement must already be certified as a “chronometer”"Chronometer" and must therefore follow, in a laboratory, the tests defined in the ISO 3159 standard.<ref>{{Cite web|url=https://www.watch-wiki.net/doku.php?id=METAS|title=METAS [Watch Wiki]|website=www.watch-wiki.net}}</ref> Finally, the movement and the watch must be subjected to 10 test cycles and satisfy to the 8 technical criteria of the METAS Requirements. The 10 test cycles are operations to be performed on each movement and each watch and make it possible to obtain the values necessary for the calculation of the 8 criteria. Among these, two are particularly demanding for the watch manufacturer, and therefore interesting for the end customer. It is first the average daily precision in 6 positions and 2 temperatures, over 4 days (4 × 24 hours). A user is simulated who wears histhe watch on histheir wrist in different positions of histheir arm; the 2 temperatures represent the temperature when the watch is worn by the user (approx. 33&nbsp;° C) and when the watch is removed (approx. 23&nbsp;° C). According to the acceptance criteria of the requirements, the watch must remain within the tolerances [between 0/≤5 to ≤5sseconds]. That is, the watch should not delay at all, and the upper limit is 5 seconds fast in 24 hours. The criterion of resistance to magnetic fields is also innovative. Until now, the '''ISO 764 Horology — Magnetic resistant watches''' standard defines that an [[antimagnetic watch]] must support a magnetic field of 4,800 A/m, which corresponds to 60 gauss. METAS certification subjects watches and movements to 15,000 gauss (1.5 tesla).

'''===Part B - Organizational requirements'''<br>===

Checks are carried out on 100% of the watches by an independent testing laboratory or by the manufacturer himself. For METAS to ensure that these measurements are always correct, a plan to monitor the testing process has been put in place. The organizational requirements are as follows:

'''===METAS infrastructure'''<br>===

The main devices are used to measure instantaneous rate (Witschi M10 Chronoscope) and daily precision (Qualima-test).<ref>{{Cite web|url=https://www.witschi.com/assets/files/sheets/Leaflet_chronoscopeM10.pdf|title=Chronoscope M10}}</ref> These two measurements are used to indicate how much the watch is advancing or loosinglosing compared to a reference clock. Instant running achieves this over short periods of time (30 seconds) while the daily precision is taken between 23 and 26 hours. The highlights of this certification are in particular the test of the resistance of the watch in relation to magnetic fields and the tight limits for the average daily precision. This being the case, the totality of the checks (magnetism, operation, and water resistance) guarantees a very high-quality mechanical watch for the end customer.

Mechanical watches can be first COSC ISO 3159 "Chronometer" certified and after that METAS N001 "Master Chronometer" certified when all the relevant requirements are met. The first mechanical watches that met the METAS Certified Master Chronometer requirements featured Omega 8900 series automatic movements.<ref>{{Cite web|url=https://www.watch-wiki.net/doku.php?id=Omega_8900|title=Omega 8900 [Watch Wiki]|website=www.watch-wiki.net}}</ref>