Omega 30mm Chronometres (EN)

Part I: The Omega 30mm caliber

This movement was designed in the second half of the 30s by Henry Kneuss (assistant technical director Omega SA) with external advice of Paul Brandt and Otto Ahrens Lucerne.

**** This article is available in both English and Italian. Questo articolo e’ sia in italiano che in inglese ****












The prototype was built by Jean-Pierre Mathey Claudet and production started in December 1938. The movement was produced, in all its various forms and subtypes of 30mm, up to 1963 – a total of about 3 million units.The continued success of this caliber was due to its precision and resistance over time, its easy regulation, the simplicity and logic design of the movement that made him a favourite of watchmakers.

All this was not the result of chance, but a consequence of the technical Omega research, which identified in previous years the ideal proportions of the various component used: the smallest escapement used in calibers of this type, combined with the largest barrel and balance permitted by the size of the caliber.

The dimensions of the caliber 30mm are: diameter 30mm, thickness 5.4 mm (subseconds variant) and 5.1 (sweep seconds). The lenght of the 30T2 hands vary according to the references, but the hole sizes are ‘0.75 × 1.40 for 30T2 and 0.95 × 1.70 for the 30T2SC. It oscillates at a frequency of 18000 A/h with a lift angle of 49 degrees.

The adjustment screws on the balance wheel (at least 8) and the bimetallic compensation (with Earnshaw cut) was the best available at that time in wristwatch movements, when performance was often proportional to the diameter of the balance wheel itself. In the image below, to the left is the bimetallic balance which was used in the 30mm calibers up to the 50s.

In post-1949 furnitures, and in 30mm movements from the 50’s, it was used a glucydur balance wheel (right), whose thermal compensation was equal to or higher than the bimetal.


The 30mm caliber was soon used in the Omega military 6B / 159, then in ‘Omega WWW (wrist-watch-waterproof, 30T2 watches that met the WWW standards published by the British Ministry of Defense).

WWW Omega together with those produced by other 11 manufacturers formed the so called “dirty dozen”. One of his later versions (cal. 283) was again ordered by the MOD in the year 1953, this time with central seconds.

Sweep seconds were introduced in 1940, using a bridge that provided indirect central seconds. This solution (already used in cal. 23.4 of 1936) was required as direct central seconds were technically impossible (excessive lost of impulse for a calibre of this size).

Starting in 1941 in some cal. 30 was introduced the so-called “de luxe finish”, a double copper plating on beryllium bronze (an alloy of beryllium and 2.25% copper) that made the movement more resistant mechanically and to oxidation, as well as aesthetically pleasing to the eye as it looked as rose gold. The “deluxe finish” was completed by curved fine brushing:

Only some movements were refinished with Côtes de Geneve or Perlage on the back surfaces of the plates, a purely aesthetic touch visible only by the watchmaker.

Another reason why the cal. 30 remains a darling of watchmakers and collectors, is the ready availability of NOS furniture. If the supplier does not have the part, it is simple to search the web using the calibre number followed by the number of part – and the success is almost guaranteed.

For the furniture lists, the pdf lists of parts can be downloaded here

cal.280, 281, 283

In the table below are described the various types of cal. 30, both with the original names, both with names that were put into use after1949 (with the prefix 26x for those with subseconds and 28X for central seconds). Source: Marco Richon, “Omega Saga”, 1998.






In watches before 1949 the movement reference was engraved on the main plate (under the balance wheel), after 1949 directly on one of the bridges.

All cases measured from 33.0 to 35.5 mm, typically snap back case in three parts with limited water resistance. Some case however had screwbacks, and other with soft iron jackets, to increase resistance to magnetic fields. Some cases (ref. 2609, 2580, 2505, 2620, 2506, 2544 and 2545) were larger and unusual for the ‘age (from 37 to 38mm) but perfect for our times.

The cal 30mm was used over the years in all its technical developments and in many types of well-known Omegas :


1- Omega WWW military and 1953 RAF (as mentioned before).

Details of these watches can be found here:

Moe (mmh):]

Franco (squelette):


2- Omega Teddington (Brazilian market)

See article by Douglas Gravina:…0673&pi=5461288


3- Omega Suveran. (Swedish market)

This was not exactly a military watch, but was produced during World War II and only for the Swedish market.

They were marked “Suveran” with the aim to strengthen the Swedish Sovereignty ‘and independence in a time of annexations, voluntary or forced. They were produced for Sweden and marketed only and put on the market only through the Swedish Ministry of Economy, which then had a monopoly on the distribution of 30mm Omega in Sweden and the resulting income. These images are from Thomas (a.k.a. “”).



4- Omega Ranchero.

The most common Ranchero reference is 2990-1, black or white dial, luminous hands and indices, 1956. Typically cal. 267 or 268.



5- Omega Railmaster.

The first Railmaster was produced in the year 1957, ref. CK-2914, cal. 284. A reference of 1961-63, the 135,004, used instead cal 286 and was used for the Pakistani Air Force.

good link:


6 – Omega Seamaster 30

They were produced in very large numbers. Inexpensive watches, they were produced in four references in the collection 1962-1963, with cal. 268/269 and cal. 286. These were ref. 125.003, 125.007, 135.003, 135.007, each available with several dial variations.

Here are some images from Thomas (


Part II: Chronometers 30mm


Observatory competitions

The astronomical observatories have been for centuries able to determine with great accuracy the time in a given place, using observation of stars in relation to the latitude and longitude of the place.

To accurately determine the time from astronomical observation during a sea journey (i.e. not in a known place) has always been problematic. In the centuries many solutions have been offered – including Galileo’s study of Jupiter’s moons and the lunar occultation of Halley. It was also proposed to measure the distance from the Moon at various times during navigation (Thobias Meyer) but none of these methods provided sufficient precision and accuracy to navigate long distances.

The Commission for the Discovery of Longitude at Sea (Commissioners for the Discovery of the Longitude at Sea, ie Board of Longitude) was formed by the British Government in 1714. The aim was to administer a series of awards to encourage inventors and scientists to solve the problem of establish longitude with accuracy in the open sea.

Prizes ranged from £10,000 to £20,000 for procedures designed to ensure a difference of longitude between 110km and 56 Km. At the time were the equivalent of £1.3 million/£2.6 million today.

John Harrison’s theory brought him to build at least five chronometers which made history. As the Earth rotates at constant speed, there is a direct relation between longitude and time. So if the sea captain could know the exact time in a place where he knew the exact coordinates, the difference between this reference time and local time, would give the ship’s position with respect to the starting point.

The problem was to have a clock on board accurate enough, despite the changes of temperature, humidity, and mechanical stresses, i.e that could maintain for weeks and months the exact time of the place of departure.

John Harrison built clocks progressively closer to ideal accuracy, very well funded but never winning the prize from the Commission. But Kendall’s K1 chronometer (copy of his H4) was aboard Cook’s ship when he first reached new Zealand and Australia. Later, “marine chronometers” became essential navigation equipment for ships, and have been used until the 70s, when other methods of localization/navigation became available.

An interesting video was produced by Nova TV based on the book: Dava Sobel, Longitude, Fourth Publisher, 1995 – ISBN 13: 978-1857025026 . This is also avaiable on Youtube (URL:

And a great book on the topic is: R. Dunn, R. Higgitt -Ships, Clocks, and Stars: The Quest for Longitude- Harper Publishing, 2014 – ISBN 13: 978-0062353566

If Harrison fostered a phenomenal evolution for timekeeping, it’s also true that the gold standard for the assessment of time and therefore ability to assess precision in timekeeping, resided in the Astronomical Observatories.

And then over the years the various European Observatories had, among many other projects, also the function to validate the accuracy of timekeeping instruments. And various Observatories launch Chronometer Competitions, – Kew in England, Besancon in France, Geneva and Neuchatel in Switzerland, Glashutte for Germany. The same Observatories also provided “bulletins de Marche” for the chronometers of various watch manufacturers.

Obviously in the different competitions, to be able to compare movements with similar characteristics, it was essential to create categories of thickness and diameter for the participating calibers. In the 40s it became obvious the importance of the races in the 30mm category, and Omega quickly embraced this racing category, designing and perfecting chronometric calibers of 30mm.

Along with the technical prowess of the watchmakers building the movements, in the “racing team” there were specialists, the “regleurs de precision”, who worked tweaking a number of movements until they could find a few of them to bring to the Observatory Competitions. By means of fine adjustments, replacement of key parts, use of special lubricants, they could create a few movements for the Competitions. And often they were the same movements for many years.

And so ‘the cal. 30 Omega, and its “regleurs”, obtained excellent results over the years in the most prestigious Observatory Competitions, by far the most successful 30mm movement ever.

To read more about racing chronometer of the last century, I would recommend:

1- Fritz von Osterhausen, Wristwatch Chronometers: Precision Mechanical watches and Their Testing, ISBN13: 978076430375, Schiffer Book publisher



2-B The first Omega 30mm chronometers : ref. 2254 and 2192

In 1941, Omega launched its first Omega Chronometer 30mm.

The watch comes in a screw case (ref. 2254) or a snap back(ref. 2192). All ref. 2254 seen so far have sweep seconds, the one ref. 2192 known has subseconds. The movement is without the “deluxe finishing” and without the special Omega fine regulation. The movements in the two watches are a 30T2SC and a 30T2, respectively.

The dials have the word “Chronometre” curved above the Omega logo, feature never seen again in Omega Watches 30mm. The 2254 has the screw back and is waterproof, the 2192 has the a snap back.

They both have double stepped lugs, and the crown is unsigned, but I have seen this very type in other Omega watches of this era.

Both Omega Extracts from Archives show that they were produced in August 1941. In both cases, the register shows that they have been delivered with a “Bulletin de Marche” – i.e they are certified chronometers. As indicated, obviously someone had regulated these Omega watches in order to improve accuracy and achieve chronometer timekeeping standards.

Two examples have been seen of another reference, the 2244 . The case is virtually the same as ref. 2192, with stepped lugs and snap back. The movement is a chronometer-grade 30T2SC with sweep seconds. The dial in both cases is not the original, so we cannot know how it was originally. The 2244, like Ref. 2192, would seem to be about 1 mm thinner than the 2254, probably for the different closure of the backs.

So, three types of 30mm chronometers with 30T2 and 30T2SC (non-Rg) are known to exist:

Ref. 2254, sweep seconds, screw back.
Ref. 2129, subseconds, snap back.
Ref. 2244, sweep seconds, snap back.

As Erich (mac_omega, PuristPro) rightly says, it has not (yet) been spotted a Ref. 2xxx with subseconds and screw back.

In this respect, I found interesting this watch, which sold at Bonhams in 2014.

The watch is, once again, from the summer of 1941 (July), and was delivered with a Bulletin the Marche. But is uses a manual wind chronometer movement , cal. R17,8 and not a 30T2. But it shows that the subsecond dial with the arched “chronometre” script existed, and it was in a screw back case- with ref 2144 however and straight lugs.

Recently another one of these, also with cal. R17,8 but with a 18K case, has been acquired by a London collector (“thetimekeeper”) who let us have these images:

A variation of ref. 2254 was later produced by Omega, but with significant differences. The dial has “Chronometre” written horizontally, and movement is a 30T2SCRg

The movement has “Deluxe finish” and has all the characteristics of typical 30T2SCRg.

The case is a screw back, but does not have the external inscriptions of the first 2254. Crown, lugs, hands are all exactly the same as the other 2254 chronometers.

An interesting detail : in the Ref. 2254 and 2192 the script “Chronometre” is above the Omega logo – which is never going to be seen again in any other 30mm chronometers .

The order of the scripts on the dial from now on will be ‘always:

1-Omega symbol




Something worth of note in the first 2254 is the presence of a single white jewel (to facilitate the visualisation of lubricants) on the pallet cock, a particular that can be found in many, but not all, 30T2SCRg and 30T2Rg calibres.

I have recently seen a 2254 (or 2244?) in yellow gold, with movement Rg and snap back. Unfortunately the dial is refinished so we do not know how it was originally.

2-C Omega Chronometer 30mm movement, i.e. 30T2SCRg e 30T2Rg

The 30T2SCRg e 30T2Rg movements certainly score very high for looks:

(Source: Marco Richon, “A Journey through time”, 2007 Omega Ltd, ISBN 978-2-9700562-2-5)

The movement structure surely is the same as a standard 30T2, but has the “deluxe finish”, i.e. XXXXXXXXXXXXXX(to be edited)   , with a very fine curved finishing (image source: SteveG’s Launchpad):

An open 30T2Rg at my watchmaker’s desk:

The chronometre movement had few structural changes from the 30mm ( cal. 260), and on the parts sheet they are so listed:

It is told that all together 18,000 chronometer movements have been used in the different references. The difference in finishing of the chronometer grade parts is visible in the next images. Many parts are mirror finished and anglaged.

The wheels seem to have deeper cut teeth, which probably can engage more consistently, but which will also probably require a better optimisation (source: SteveG’s Launchpad). MauriceDV (O+P) believes however that rather than length, the cutting of these chronometer wheels was done with special care in respect of the epicyclic profile . It is well known that in the competition chronometers… the régleurs would spend much of their time on optimisation of the wheels, mirror polishing pivots, pinions and spindles to reduce friction, reducing tolerances to a minimum. Between these things, the care of the wheels was obviously very important (MauriceDV)

But the most notably different part is the “Special regulation” system (source: SteveG’s Launchpad):

The parts of the regulation system are specific for these calibres:

But they have also been later used in in other chronometer movements, like the bumper cal. 343 of 1950:

Another chronometer grade part is the balance wheel, which is bimetallic for temperature compensation, and with an Earnshaw cut.

The Earnshaw cut is right close to the spokes of the balance wheel, while the Guillaume cut (a characteristic of the celebrated Guillaume balance) is more distant from the spokes. This is very visible from this image which was posted by my friend Nicola1960 (O&P) :

Here are images of the balance wheels complete (part n. 262-1327), original Omega part. Bimetallic, with regulation screws, Earnshaw cut (i.e. type 1 in Nicola’s image).

(source: SteveG’s Launchpad)

Please note that in the Omega parts catalogue from the 1950s, the balance wheel (part 262-1327) was changed in a monometallic, uncut Glucydur unit, with compensating screws (see type 3 in Nicola’s image). Movements produced in the 50’s also used the Glucydur balance.

An interesting question was if, with the change of nomenclature of 1949, it was ever produced a movement with the inscription “262” or “281” on the bridge, instead of 30T2SCRg / 30T2SC on the main plate. The answer is’ probably not , but the inscription was there on bridges supplied as parts post-1950. Note the absence in the image of the serial number, which was then added according to the serial number of the replaced part, but with the prefix “R” (for “Replaced”).

It would look like, however, none of these different Rg parts actually had little to do with the performance in timekeeping at competitions. One of the foremost Omega collectors, Erich (mac_Omega) of, has recently acquired this chronometer Omega 30mm in full competition gear:

It ‘s remarkable to see its “normal” adjustment , basic finishing, and the Guillaume cut balance wheel (type 2 in Nicola’s image) as specified in the “Bulletin de Marche”.

Obviously the “Regleurs de Precision” were using a different type of balance wheel in the competition 30mm, than in standard Rg, as also seen in this other example (Guillaume balance):

In the races the various movements were tested in different positions and temperatures, and in some races also at different levels of mainspring tension:

It is interesting to see the papers given with the watch at the point of sale:

The “Certificat de Marche” does not specify the type of balance used, but of the many 30T2SCRg and 30T2Rg that I have seen, none had a Guillaume. All with a compensated bimetallic Earnshaw cut balance wheel, sometimes visibly less refined because replaced at some point with one from a 30T2 (after changing the balance staff, as the Rg had no Incabloc).


Part III: Chronometers 30T2Rg and 30T2SCRg

3-A References 2364, 2365, 2366 and 2367.

These are by far the most common 30mm chronometer references:

2364 33mm case, 30T2Rg
2365 33mm case, 30T2SCRg
2366 35.5mm case, 30T2Rg
2367 35.5mm case, 30T2SCRg

Case Ref. 236x was produced in three parts – bezel, carrure and snap back. The case back of the steel models has the reference indicated inside, gold cases instead have a case serial number, the gold hallmark and Omega symbol.

The cases were produced in steel, 18k rose gold, 14K and 18K yellow gold. Some models (especially for the Argentinian market) have a 14k rose gold bezel and stainless steel case. The cases of 2366 and 2367 also had a brass retaining ring.

The crowns were usually not signed. Over the years many watches have received more recent Omega crowns, thin and about 6mm in diameter.

Here is a series of original dials, which together with the advertising (see below) may provide elements to recognize an original Omega dial form the many refinished dials.

These dials are called “scientific” type, and are characterized by quadrant hairlines and applied indices on a silver rail, brushed in a circular fashion.

The following are similar, but with Arabic numerals and a different silver rail.

These dials are two-tone and printed (“indelible” printing) with art deco numbers.

Other dials also typical of these chronometers:

A rare dial for ref. 2366 has recently been posted. It has no applied indices,  no swiss made, no luminous.

3-B Uncommon and rare References

3-B-1 Ref 2410

The 2410 is one of the two 30mm chronometer references with screw back (the other is the 2254 which we have already’ seen. This reference only uses only the 30T2SCRg with “deluxe finish”.

These are two examples from Bill Sohne, which are the two types of the existing 2410: CK2410, 30SCRg steel and CO2410, 30SCRg steel with 14K gold bezel. Bill Sohne was the Omega collector responsible for introducing me to the 30mm chronometers some 15 yrs ago.

And this is my 2410, with radium original indexes (checked with Geiger counter):

The case back shows many signatures of watchmakers who have worked on this 30T2SCRg. Note that in this reference there is always a retention ring rather than the two classic case screws. In this watch of mine I have not (yet) changed some parts that are standard finish 30T2 (1100- Ratchet wheel; 1101-1102 crown wheel and core; 1104- click). I have the necessary parts, but I never had the watch serviced.

This is a beautiful 2410 from msn_watch, PuristPro Omega.

One other particularity of this reference is the presence of a three digit number in the caseback, which is repeated in the carrure. It should be an “internal reference” to help assemblers to always have a correct closure of the case.

Two specimens whose photos have appeared online, note the splendid specimen with anthracite dial.

3-B-2 Omega chronometer ref 14159 and ref. 2363

Of this type I have seen only two watches. The first, which I still have, went to Bienne for a complete service and installation of a dial chronometer that, in 2001, they still had in stock. If it had been reprinted in-house I do not know, but the previous dial was of exactly the same type (but a bad redial).

Mr. Diethelm from the Omega Museum identified a it as a ref. OT 14159. On his book “Journey Through Time” Marco Richon refers to it as OT 14159.

The second, which I bought in Pistoia (Italy) and only kept for a few months, has later been very well documented by its new owner, my friend Roberto Ortolani. Here are his photos of the watch:

Roberto Ortolani was able to also obtain an image of the fiche from the Omega records (see below), which identifies it as a ref. 2363

I have no idea why they seem to have two different references in Bienne, and would not rule out that there may have been a mistake at some level.

3-B-3 Fab Suisse

These are chronometers with cases produced in Omega Besancon (MBF, Maison Brandt Freres) and have dial marked “Fab Suisse” to indicate that the movement is’of Swiss origin. The design of the case is in my opinion very clean and sharp.  Particularly love the distinctive lyra-shaped lugs.

On the back of the case there is the Omega logo, serial number, gold hallmark and the Falcon, a symbol of 18K gold in France.

As we see from this extract, the movements were sent as such to Omega Besancon, which then provided dials and cases.

Here is another one sold online very recently. Note the serial numbers very close to the other one, and the inscription “Fabrique en Suisse” on the movement.

A second type of “Fab. Suisse” Rg Chronometre has straight and chunkier fixed lugs, needing female springbars. These are pictures provided by Michael Cohen (merchandiser):

It has recently (May 2019)  come up for auction at Antiquorum a rare reference of 30mm chronometre, the ref. 14169. The large case (37mm) is very similar to the Vacheron 4907 and has straight and chunky lugs.   Case produced at least in 18K yellow and  18K pink gold.

Having immediately looked back in the web for this reference,  have found other ref 14169 chronometres posted in the past.  The one below  on the right is the one referred to in the current Antiquorum auction  (from 2004):

The movement is a “standarg” Rg, and of a comparable serial number to the 236X production:

3-B-4 Omega 30T2SCRg piece unique by Benzinger

This chronometer was my number 13 , around year 2003-2004. It turned to be a watch full of bad luck, as the dial within weeks started to darken with exposure to air, and the movement was serviced by a well-known austrian watch master , but in his enthusiasm the finish to the movement changed irreparably.

I decided to turn the bad luck into an enjoyable piece, and I sent the dial to Jurgen Causemann and the watch to Jochen Benzinger, then a famous artisan who was not yet the superstar of today.

Jochen had a small workshop in Pforzheim, with a large number of machines for guilloche (engine turning) and only three people in his group. He was already making small editions for IWC and JLC.

At the base of my “folly” was a mistreated ref.2367. This was the finish to the movement:

I had seen other Benzinger watches with a partial skeleton, against a mainplate plate in blue. And this was the final effect in my Omega:

In intermediate stages of work, the bridges were marked and prepared with plating before cutting the various bridges and working on the back plate:

This was the result of the work from Benzinger:

The dial was given new life by Jurgen Causemann:

And at the end, a sapphire window was inserted in the caseback:

Obviously, I requested specifically that all the inscriptions and typical parts of the chronometer were maintained, to retain some identity to the watch.

I have received massive amount of criticism for this watch, but honestly seen the initial conditions – well different from the original watch – I remain very happy of the choice.

3-C “Nearly chronometers”

I think it’s appropriate to have a section on “nearly chronometers”, because the web is full of offers of “chronometers Omega” swhich in fact have nothing in common with real chronometers.
But also there are some “non-canonical” chronometric calibers, in which the intent of the manufacturer was clearly to produce a specially regulated watch.

Omega Teddington

Omega Teddington are watches for the Brazilian market, characterized by a strong timekeeping performance, a star on the dial – but without specific chronometric parts. They were launched in 1940, nearly three years before chronometers Rg.

From the description of Ref. 2271 in the Omega Vintage Database: “The red star which is sometimes featured under the Omega logo identifies the watch as being equipped with the same type of caliber as the one obtaining the best results in the 1940 Kew Teddington precision competition.”

This does not mean that any Omega 30mm, with dial reprinted with star, is a Teddington. It must first be one of ref. indicated (CK2271; DR2189; OT2271), then be delivered to the Brazilian market, and have these characteristics confirmed in the Omega extract.

Here are some from our good friend Douglas Gravina:

Another Teddington was produced later (1954-1955) and is the ref. 2619:

The 2619 was also produced for the Swiss market. It ‘s not clear, however, if all the Ref 2619 were Teddington quality.

Cal. 283

According to Bienne, the Omega Pilot ’53 (ref. 2777-1) was fitted with a caliber 30 SC T3 – 283, with “special adjustment in four positions to less than 10 seconds per day”. This shows how it was possible to adjust these calibers to obtain precision timekeeping. The case and its antimagnetic performance also proved extremely functional, and became the basis of “Railmaster” of 1957. That does not mean however that all the 283 on eBay can be passed off as chronometers.

But there are rare 283 where the Omega took a step further:

Let’s take a step back. Bill Sohne had found a very uncommon Railmaster, both for its dial and its movement:

The three very unusual things of this watch were:
1- the case reference (the 2777-1 was that of ‘Omega Pilot ’53)
2- the dial, which was a white version of the Omega Pilot, but without Pheon
3- and the movement which had a “swan neck” micrometer adjustment.

It seemed an absurd combination of events (among other things it had never been seen a swan neck on a 30mm), but after exhaustive communications with the Omega Museum, these were the conclusions: the movement was genuine, and one of very few 283 products produced wit the swan neck regulator.
The drawings were found in the archive (see above) and had a scribbled in pencil phrase “Cancelled on December 14th 1957” on it – so it never entered large production.

In time, Bill has found ten of these movements in the hands of several collectors, and almost all of them were originally delivered in Canada.

And his “Railmaster” has entered the book by Marco Richon, “A Journey Through Time”:

Omega ref 1894 centennial

This triplet was launched in 1994 to commemorate the centenary of the birth of Omega. On this occasion, Omega used the cal 269 and 286, which had been discontinued for the past three decades.

This limited and numbered edition was offered as 100 sets of all three versions, plus 1894 watches in 18K rose gold.

1- Ref. BA 135.1894 in cloisonné dial with a floral motif, 18K yellow gold case, cal. 286, monometallic balance, incabloc, case 35.7mm, thickness 11.2, see through back. On the back are reported details about the limited series and serial number.
2- Ref. AT 125.1894, two-tone silver dial , platinum case.
3- Ref. 125.1894 BG, two-tone rose gold dial, 18K rose gold case.

The last two had the cal 269, monometallic balance , incabloc. Even without the classical chronometer-grade parts, this renewed movement offered chronometer-like timekeeping.

Certainly the aesthetic of classic chronometers was not recreated (wheels not mirror polished, standard regulator, click and accessory ratchet core), but as a product of the 90’s these movements offer performance of all levels, and also Incabloc which was missing in the original timepieces.

Omega ref. 1894 for the Japanese market

These were produced in a limited edition for the Japanese market, with completely different dials from those of the centenary. There were 1894 for each of the three version. All are with a 18k rose gold case, diameter 35.8, 10 mm thick. In all of them the 269 caliber and inscriptions relating to the limited series. All are ref. BG 125.1894.

3-D Accessories and advertising


These watches were probably sold in one of these two types of boxes:

A specific case for the chronometer does exist, with satin and velvet interior in brown, ivory or gold in various combinations:

The type of documentation that was supplied with the chronometer is visible in this advertisement. On the bottom right (highlited in red) I have included the “Certificat de Marche” as we have seen. The absurd bracelet in the image had to be censored (sorry).

Buckles and straps

Very little facts are certain about buckles and straps of these watches. From advertisement of the era we can guess that most of the leather straps were very simple (probably pigskin) , of various colors, with stitches at the edge, near the lugs and the buckle.

Buckles, as well as crowns, did not have the Omega brand. Specimens of the ’50s were probably the first buckles signed simply “Omega” on the back. Something like this:

Advertising material

These are ads from the era, which I have seen and accumulated over the years:

And this is the cardboard booklet , with four pages showing details f the 30T2Rg , which I acquired a few years ago:


A great new book on these Omega Chronometres:

I have just received (12/05/2019) what I consider the new Bible of this area. It is written by Erich Lexer (mac_omega on various forums), who is simply (apart from a friend) the only person I can refer to in this niche topic, more than Bienne, more than anyone else.

The book is called “Omega 30mm Chronometer”, and is huge both physically and by its contents.

Obviously I was familiar with many topics, but for example I only  now have learnt of the existence of certain other chronometric references, of the exquisite details of versions for specific markets (even of the “FabSuisse” ones for the French market – which I thought I knew) , and many other small things of enormous interest for the enthusiast but also the merchant or the expert.

In short, I spent (and will pass) the next weekends with this book, and enjoy any moment of it.

PS: Just to clarify, I have no personal interest – I paid in whole for the book and I intend to consume it with the power of my eyes!

Contact the author to find out more:



Looking at the final result, I realise that to write a history of the 30mm and chronometers 30T2SCRg and 30T2RG, has been a bit too ambitious. And therefore also far too long.
And of course, it may contain errors or inaccuracies, so I would be more than happy if I could have your constructive criticism, comments and perhaps additional material that you think would be suitable to be inserted.

I would like to thank my mentors in the area, primarily Bill Sohne and Christian Rothe. And also other experts on the subject, mainly Erich (mac_omega) and SuitbertW (PuristPro) for their contribution, even just through reading their posts on various international forums.