RolexCopyright © Notice
The story of the Rolex watch is inextricably entwined with the story of Hans Wilsdorf, who co-founded and personally drove forward the progress of the company, and the technical developments that led to the public acceptance and expectation of an accurate, waterproof, self winding wristwatch. Many others contributed, and there were waterproof and self winding watches before the Rolex Oyster, but the fact remains than Wilsdorf is an important figure in the story of the modern mechanical wristwatch.
This picture of Hans Wilsdorf is from the Rolex Jubilee Vade Mecum published by the Rolex Watch Company in 1946. The Vade Mecum takes the form of four small booklets in a slip case, and was printed in a limited edition of 1,000. The booklets are:
- Step By Step
- The Evolution Of The Wrist Watch Chronometer
- How The Waterproof Watch Came Into Being
- The Story of the Self-Winding Watch
I have copy number 619, except for volume three which is from copy number 270. All four booklets are stamped "Rolex Watch Division, C.P.O. Box 721, Tokyo, Japan" so I guess they must have all been in the same office at one time and one got switched around. If the owner of Rolex Vade Mecum 270 reads this and wants to swap volume three, then please get in touch!
If you have any questions or comments, please don't hesitate to contact me via my Contact me page.
Hans Wilsdorf - Early Days
Hans Wilsdorf was born in Kulmbach, Bavaria, Franconia (Germany) on 22 March 22 1881, the second son of a family of three. His mother's early death was soon followed by that of his father and in 1893, when he was 12, his uncles decided to liquidate his father's business and use the proceeds to place the children in a very good boarding school in Coburg. Wilsdorf showed a particular liking for mathematics and languages, which drove him to travel and work in foreign countries. He apprenticed at a firm of pearl exporters whose sales organisation covered the whole world, which experience he felt was invaluable throughout his whole career.
In 1900, aged 19, Wilsdorf started work at the major watch exporting firm Cuno Korten in La Chaux-de-Fonds, Switzerland, as their English language correspondent and clerk at a monthly salary of 80 francs. La Chaux de Fonds, along with Geneva, formed the hub of the high-quality watchmaking industry at the time. There, Wilsdorf was exposed to the most influential people and practices in watchmaking, which would later be an important asset in the founding and success of Rolex. In 1903 Wilsdorf moved to London to work for another watch making firm. Growing in confidence with the experience he gained from this and his previous employment, he set about establishing his own firm.
Foundation of Wilsdorf & Davis
In 1903 Wilsdorf moved to London, where he worked for a watchmaking firm. Two years later, in May 1905 at the age of 24, he borrowed money from his sister and brother-in-law Alfred Davis, and founded the firm of Wilsdorf & Davis, 83 Hatton Gardens, London E.C. Their first speciality was a travelling watch, called a portfolio watch cased in fine quality leather. But Wilsdorf was convinced that the wristwatch was the way of the future. In the Vade Mecum he says that the he thought that there would be a better trade in wristwatches than in pocket watches, partly because they were more prone to damage, and partly because, unlike a pocket watch that was handed down from generation to generations, wristwatches would be fashionable items that would be personable to their wearer, who would also want to have two or three to go with different outfits. Wilsdorf was not really interested in watches per-se, he was thinking like the marketing director of a brand.
In 1902 while in La Chaux de Fonds, Wilsdorf had become acquainted with the firm of Hermann Aegler in Bienne, who produced a small lever escapement movement with a reputation for precise time keeping and good availability of spare parts due to the modern precision production methods pioneered by Aegler, making extensive use of machinery so that parts were interchangeable. In 1905, soon after founding his firm in London, Wilsdorf went to Bienne to see Aegler and placed the largest order for wristwatches ever seen at that time. Wilsdorf says that the first wristwatches produced under this arrangement were men's and ladies in silver cases with leather straps and that their immediate success after the autumn launch prompted him to introduce a selection of designs in gold cases. In 1906 the expanding bracelet was launched by an important jewellery firm, and Wilsdorf immediately made this available as a very popular option on his wristwatches. Wilsdorf doesn't say so in the Vade Mecum, but these expanding bracelets would have been for ladies wristwatches. An attempt to introduce a similar expanding bracelet branded "Army" during the Great War, emphasising the benefits of a metal bracelet over leather in wet and muddy conditions, fell upon stony ground because of its effeminate appearance, despite the brand. I very much doubt that many of these first wristwatches were sold to men, despite what Wilsdorf says.
W&D: Wilsdorf and Davis punch
Wilsdorf & Davis sponsor's mark
To send items for assay and hallmarking it was necessary for details to be registered with the assay office, including a UK address and the mark made by a punch used to identify each item that was sent in. This W&D is the sponsor's mark of Wilsdorf & Davis, recorded in the register as importers of gold and silver wares, first registered at the London Assay Office on 25 June 1907. A second punch with the same mark was registered on 13 August.
Until 1907 Wilsdorf & Davis imported gold and silver watches with Swiss hallmarks, but British law changed in 1907 and from 1 June 1907 all imported gold and silver items were required to be assayed and hallmarked at a British assay office. This is the reason for the registration of the W&D sponsor's mark in 1907. Items imported from Switzerland by Wilsdorf & Davis before 1907 would have been assayed and hallmarked in Switzerland, but once the UK law was changed and Swiss items had to be hallmarked in the UK they were no longer hallmarked in Switzerland.
The registration of two punches on dates so close together indicates that the second punch was required to keep up with the volume of work rather than replacing a worn out punch, so Wilsdorf & Davis must have had two men working full time punching items that were to be sent for hallmarking.
The following information is gleaned from Culme John Culme "The Directory of Gold and Silversmiths, Jewellers and Allied Traders, 1838-1914: From the London Assay Office Registers" Publication Date: 15 Oct 1987 | ISBN-10: 0907462464 | ISBN-13: 978-0907462460 Two volumes; the first with 4,000 biographies, the second with photographs of 15,000 marks taken directly from the London Assay Office Registers at Goldsmiths' Hall. . The partners in Wilsdorf & Davis were Hans Wilsdorf and Alfred James Davis. The address recorded at the registration of their punches was 83 Hatton Garden, later recorded on 1 November 1907 as moving to 85 Hatton Garden, EC1, then between 17 August 1912 and 25 August 1919 they are recorded at Stevenage House, 40-44 Holborn Viaduct, EC, where they are listed in 1913 as watch manufacturers and importers (TA: 'Wilsdorfs'). Wilsdorf & Davis are also recorded on 8 April 1915 at 15 Northampton Street, Birmingham, and also 3 Ruelle de la Fabrique, Bienne, Switzerland. They are recorded 25 August 1919 as having an office at 61 Rue Elfenau Gare, Bienne, Switzerland, in addition to their London office, and also as representatives of the Rolex Watch Co. Ltd. whose chairman was Hermann Aegler with Hans Wilsdorf and Alfred James Davis as directors and Harry Sedgley as secretary.
Before the Great War (1914 - 1918) London was the export centre for Wilsdorf and Davis for every market in the world. The watches were made in Switzerland by Aegler,but every watch was examined in London before sale. In 1915 the British Government imposed an ad valorem duty of 33⅓% on imported luxuries, including clocks and watches, to conserve foreign currency reserves as part of the war effort. This meant that any watches imported into London, even if only for checking with subsequent export abroad, would be subject to this high rate of tax.
Because of this high rate of tax, Wilsdorf turned to the Dennison Watch Case Co. for gold watch cases of all grades for any watches imported for sale in Britain. Silver watches being less expensive were not so affected by the tax and silver watches watches imported for sale in Britain continued to be cased in Switzerland, in Swiss made cases.
To avoid paying import duties on watches that were not destined for sale in Britain, Wilsdorf moved his inspection facilities to Switzerland. Gold and silver watches for his other markets, principally the British colonies and overseas territories, were all made and cased in Switzerland, and then exported direct to the counties where they were to be sold, bypassing Britain and the British tax.
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Aegler supplied Wilsdorf & Davis with movements manufactured in its ebauche factory in the Rebberg district of Bienne and hence these early movements are often referred to as "Rebberg" movements, even if they are not stamped with the Rebberg name. Rebberg was a registered trade mark of Aegler.
Wilsdorf had the movements supplied by Aegler fitted into cases in Switzerland, or sometimes in England by the Birmingham case maker Dennison. Aaron Lufkin Dennison (1812-1895) had pioneered mass production watch making in the USA, but ran into financial difficulties in a turbulent financial period in 1857. In 1862 he moved to England and set up the Dennison Watch Case Co. of Birmingham. Watch cases supplied to Wilsdorf & Davis were usually stamped "Dennison Watch Case Co" but Dennison also used the case maker mark "ALD" for Aaron Lufkin Dennison. It seems that Wilsdorf & Davis imported watches already cased in silver cases and used their own sponsor's mark when these were sent to be hallmarked, but that it was better economically to have the more expensive gold cases made in Britain and then the movements put into them in the UK to avoid the high import taxes on the gold.
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Rolex and other brands
In 1907 Wilsdorf opened an office in La Chaux-de-Fonds for marketing purposes. Wishing to create his own brand he started using this Swiss office to register brand names. The first he name he chose to register was "Lusitania", on 1 November 1907. Lusitania was an ocean liner launched by the British Cunard Line in 1906, the biggest, fastest and most luxurious liner in the world at the time. In 1915 Lusitania was torpedoed and sunk by a German U-boat, an event that brought America into the Great War on the side of the Allies, but by then Wilsdorf had long since lost interest in the name.
First registration of the Rolex name in 1908
In 1908 Wilsdorf coined the name Rolex. Some have speculated that this had some complicated origin such as being derived from hoROLogie EXcellence, but in the Vade Mecum Wilsdorf says that Rolex was chosen because it was a short yet significant word, not cumbersome on the dial (thus leaving room enough for the inscription of the English trader's name) and, above all, a word easy to memorise. It has a pleasant sound and its pronunciation remains unvaried in whatever European language it is spoken. But he doesn't reveal where the name came from, so we shall probably never know. His description of the way the word is short, easy to remember and pronounce echoes the words of George Eastman, who registered the trademark Kodak on 4 September 1888. Eastman said his criteria for the name were that it should be short, one cannot mispronounce it, and it could not resemble anything or be associated with anything but Kodak. I am sure Wilsdorf had the same considerations in mind when he devised the name Rolex.
Wilsdorf registered Rolex as a brand name in La Chaux-de-Fonds on 2 July 1908 as shown in the registration details reproduced here. This shows that Rolex is a trademark of Wilsdorf and Davis, manufacturers of watches, parts of watches and cases. Wilsdorf requested Aegler use the new trademark on all of his watches. Aegler wanted their own name to appear on the watches they manufactured, but reluctantly agreed to Wilsdorf's request. Wilsdorf wanted to create a brand that would distinguish his product from other watches, which may even have contained the same parts - Aegler was not an exclusive supplier to Wilsdorf at that time, and also supplied movements to Gruen. Aegler registered Rolex as a trade name in 1913 for the manufacture of watches and watch parts.
Wilsdorf was extremely pleased with the name Rolex and decided to keep the brand name Rolex for only his most expensive watches, but he also realised that markets existed for watches to be sold at lower price points, so over the years he created many other brand names to fulfil this demand. The first of these, registered in July 1909, was Omigra, which looks suspiciously like Omega, a brand that was well known and prestigious long before 1909, when the name Rolex was of course still new and unknown. Wilsdorf must have had second thoughts about this and the registration was cancelled four months later at his request. One of the next brands he created was Marconi, after the inventor and wireless telegraphy pioneer, which was followed by Unicorn, RolCo, Oyster Watch (which was rather confusing as there was also a Rolex Oyster watch) and many, many, others, one of the best known these days being Tudor. The Marconi name was the only one of the first few that was used to any extent, and then in the 1920s the Unicorn name took over from Marconi.
There was never any secret that these watches were made by, or rather made for, the Rolex Watch Co., but they were not called Rolex watches or branded "Rolex". The distinction he created was subtle, but Wildsdorf was a master salesman who was expert at manipulating names and brands, the first modern marketing expert. Omega did the same thing with Tissot; In Omega - A Journey through Time Marco Richon explains that in 1935 an economic collapse in Brazil made it impossible for Omega to maintain sales at Omega's normal price points. Rather than cut prices just for Brazil, which would have inevitably affected Omega branded watches sold in other markets, the company withdrew Omega marketing and sales from the country and branded watches sold in Brazil at lower price points "Omega Watch Co. - Tissot".
Today one sees Marconi and Unicorn watches being advertised (not by Rolex I hasten to add, but on internet web sites) as "early Rolexes". This is not entirely accurate, but ephemeral things like brand identity are not black and white, which is clearly what Wilsdorf himself had in mind. He wanted purchasers of the "other brand" watches to feel that they were getting a Rolex at a cheaper price, whilst at the same time persuading some other people that it was worth paying more to get a watch with the Rolex brand on it. The Tudor brand was launched in 1926 and Wilsdorf is reported to have said at the time For some years now I have been considering the idea of making a watch that our agents could sell at a more modest price than our Rolex watches, and yet one that would attain the standards of dependability for which Rolex is famous. It is called the Tudor Watch Company.
So is, for example, a watch with the name Unicorn on the movement and the W&D sponsor's mark in the case back actually an early Rolex? No. It is a watch that was made by, or perhaps we should say made for, the Rolex Watch Co., but they would have called it a Unicorn watch, not a Rolex. It is an early Rolex Watch Co. product, but it is not an early Rolex watch, although it clearly is a watch, and it was made by, or for, the Rolex Watch Company. The situation is even more confused for some early Tudor watches that have Tudor on the dial, often with the name of a Rolex model such as Oyster Prince, and Rolex inside the case back along with the Rolex trademark crown with the five points with balls on their ends. Tudor was later separated from the Rolex brand and stopped using the Rolex name and trademarks.
However, and this is probably the critical point as far as most people who are not professional hair-splitters are concerned, a watch made with one of these "other" Rolex brands would not have left the factory with the "Rolex" brand on the dial. If it has Rolex on the dial now, then that has been added later by someone else. You don't think that whoever did that might have been trying to deceive you do you? Dear me, what an unpleasant thought. Whoever it was, it certainly wasn't me. As to the question of whether a watch is really a Rolex if it doesn't have, or shouldn't have, Rolex on the dial, I think I have made my views clear, but ultimately it comes down to your views and what you are happy with. But give thanks to the marketing people who took the idea of brand names, which were originally conceived to give people something they could trust, and made them into slippery creatures to manipulate desires and expectations.
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Rolex on the dial
Early Rolex watches, by which I mean before about 1925, are often clearly marked Rolex inside the case back and on the ratchet wheel, as well as carrying the W&D sponsor's mark if they are in gold or silver cases and carry British hallmarks. These watches usually do not have the Rolex name on the dial, but occasionally one finds one that does and the question is asked; is this original? I don't think that it is, I think that if early Rolex watches like this carry the Rolex name on the dial it was applied after it left the factory - and probably quite recently. Why do I think this, well, it's a bit of a complicated story, but here goes . . .
Wilsdorf began his business in London in 1905 as an importer, ordering watches from Swiss manufacturers and selling them to British retailers. Until 1 June 1907 these watches would have carried no signs that Wilsdorf had ever had anything to do with them. Gold and silver watches would have Swiss hallmarks inside the case back and "Swiss made" on the movement and dial. But from 1 June 1907 imported gold and silver watches were required to be assayed and hallmarked in a British assay office, so Wilsdorf had to enter his details and a sponsor's mark, the well known W&D in a shield with points top and bottom, at the London Assay Office at Goldsmiths' Hall. Imported gold and silver watches were stamped with this sponsor's mark before being sent for hallmarking. It might have been this development that eventually gave Wilsdorf the idea that he could put his own brand onto watches that he ordered from manufacturers in Switzerland.
This gives rise to another question that comes up quite often, is a watch that carries the W&D mark but no other marks actually an early Rolex? In my view the answer must be no. Wilsdorf was very proud of the brand name Rolex and only used it on watches that he was proud to put his name to. Watches sometimes turn up with the W&D mark that are not of the top grade, with unjewelled trains for instance. These are sometime thought to have forged W&D marks, but I think it is more likely that in the early days when Wilsdorf was getting the business off the ground he would import anything that he thought he could make a margin on, but he didn't give these the Rolex name.
My grandfather's 1918 silver Rolex wristwatch
No sign of Rolex on the dial - or any name in fact
In my view, unless the watch carries factory applied Rolex branding, then Wilsdorf wouldn't have regarded it as a Rolex, and neither should we. By factory applied branding I mean the name Rolex either stamped into the case back, engraved onto the ratchet wheel, or fired into the enamel of the dial. Of course any of these can be faked, someone could get Rolex and W&D stamps made to mark case backs, could engrave Rolex onto a ratchet wheel, or take one from a scrap movement, or could paint Rolex onto the dial. Of these, putting the name Rolex onto the dial is the easiest to do, but also the easiest to detect, because with a touch of solvent the paint will dissolve. The same as happens to retailers names painted on to enamel dials. I am sure that when Wilsdorf started applying Rolex branding to watch dials, this would have been fired into the enamel and impossible to remove.
So when did Wilsdorf start applying factory Rolex branding to watch dials? In the beginning, in common with almost all other watches sold in Britain at the time, the Rolex name was stamped or engraved on the case and movement only; the dial was left free for the retailer to apply their name. To start with Rolex was a new and unknown name whilst most of the stores they supplied had been in business for a long time. Naturally people would have more faith in a watch with the name of "Asprey" or "Harrods" on the dial, rather than the unknown Rolex. This might not have been the case for markets outside Britain, of which more below
Wilsdorf had great difficulty in getting British retailers to accept the name Rolex on the dial as he explains in the Vade Mecum Despite the qualities of [the Rolex] name, it took twenty years of hard work to make the idea acceptable in England. At first, I ventured to inscribe it on one watch in every six; then it appeared on two, and later three, in every six. This half victory was still unsatisfactory and we knew that it would take many more years to obtain the desired result. Tired of waiting, in 1925, I decided to launch the "Rolex" trade mark by means of an intensive advertising campaign. The policy entailed annual expenditure of more than £12,000 - not for one year alone, but for several in succession. One of the results thus obtained was that dealers agreed first that four, and later five, out of every six watches should bear the name of "Rolex". At last, in 1927, the waterproof "Rolex-Oyster" was launched and we were then in a position to announce definitely that in future not one of our watches would ever again leave our works without our name on the dial, inside the case and on the movement.
Note that Wilsdorf says that one of the reasons he liked the name Rolex was that it was not cumbersome on the dial (thus leaving room enough for the inscription of the English trader's name) (emphasis added) and that it took twenty years of hard work to make the idea acceptable in England (emphasis added). His initial idea was clearly that the name Rolex would be placed on the dial whilst still leaving room for the English retailers name, but the retailers were not amenable. Britain and the empire was an important market for Wilsdorf and Rolex, which may be why he concentrates on this point. But is is clear that had the English retailers not prevented him from putting Rolex on the dial he would have been at it like a shot.
Wilsdorf is rather vague about what date he means when he says At first, I ventured to inscribe it on one watch in every six; He says the struggle took twenty years, and that At last, in 1927, the waterproof "Rolex-Oyster" was launched and we were then in a position to announce definitely that in future not one of our watches would ever again leave our works without our name on the dial ... Twenty years before 1927 would be 1907, when Wilsdorf had only just thought of the name Rolex. The implication of this is that right from the start one in every six British imports, which can generally be distinguished because cases at the time were usually gold or silver and carry British import hallmarks, would have had the Rolex name fired into the enamel at the factory. But I suspect that Wilsdorf is stretching the facts and that it was not actually until the 1920s that he really started on this campaign. After all, if he was so impatient and really had started in 1907 with one in six, why would he have waited until 1925 to get the proportion up to four in six? That doesn't ring true to me.
I am sure that factory original names on enamel dials would have been applied whilst the dial was being made and fired into the enamel along with the minute tracks and hour numerals. This would have been easy to do, and the most durable, and I can't see why a name would have been painted on later unless it was not known at the time the dial was made. An easy way to test whether a name or detail is fired into enamel or has been painted on after an enamel dial was made would be to see if the detail is removed by a solvent. Factory applied names on enamel dials would usually be fired into the enamel and therefore resist solvent. But before doing this test, please be sure that you are not about to ruin an original dial!
It can be inferred that for markets other than Britain, Wilsdorf might have insisted on having Rolex on the dial from an early date, possibly even as early as 1908, so it seems at least a possibility that there may be Rolexes from as early as 1908 with the name Rolex fired into the enamel of the dial, but these would have been for other markets and not have been imported into Britain so would not carry British import hallmarks. Personal imports where someone buys a watch abroad and then returns to Britain are not required to be hallmarked.
If you have a pre-1925 Rolex with an enamel dial that has Rolex fired into the enamel, and the case has British import hallmarks, then do let me know. Of course just one example may not be proof, the dial could have been changed for instance, we really need a few hundred examples to be sure.
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Wilsdorf was a perfectionist and never ceased pressing Aegler to improve the timekeeping of watches they made for him. In 1910 Aegler submitted as its manufacture a Rolex wristwatch to the Bienne testing station at the School of Horology. On March 22nd 1910 this watch received a First Class certificate and thus became the first wristwatch to be officially certified as a chronometer in Switzerland.
NB: Chronometer refers to a precision watch that is tested in various temperatures and positions, thus meeting the accuracy standards set by the official institute in Switzerland, which is only achieved by the finest quality movements. It should not be confused with Chronograph, which refers to any watch with a stopwatch function, whether the time keeping is of high accuracy or not.
On July 15th 1914, a small 11 ligne (25mm diameter) Rolex wristwatch received a Class A precision certificate from the prestigious Kew Observatory in England. This was the first time that a Kew "A" certificate had been awarded to a wristlet watch, and required that the watch pass the same tests as large marine chronometers. The watch was tested over 45 days in five different positions and three different temperatures, including ambient (65 degrees Fahrenheit), oven-hot, and refrigerator-cold. Wilsdorf said that this was a red letter day in the development of the firm, a day that he would never forget. Wilsdorf asked Aegler from then on to submit all Rolex calibres for chronometer tests. The ability of a wristwatch to maintain accurate time keeping could no longer be doubted.
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The Great War
With the outbreak of the Great War (World War One or WW1), soldiers wanted reliable and accurate wristwatches and, as they were not issued with them as standard equipment, they bought their own. This presented an opportunity for Wilsdorf to sell more wristwatches, but the war also led directly to some serious problems. Before the war London was the export centre for Wilsdorf and Davis for every market in the world, with every watch they sold being examined there. By 1914 the firm had grown to such an extent that it was occupying a large suite of offices and had a payroll of more than 60 employees. In 1915 the British Government imposed an ad valorem duty of 33⅓% on imported luxuries, including clocks and watches, to conserve foreign currency reserves as part of the war effort. This meant that any watches imported into London, even if only for checking before subsequent export abroad, would be subject to this high rate of tax.
In 1912 Wilsdorf and Davis had opened an office in the Aegler factory in Bienne to facilitate their close business relationship with Aegler. As a result of the British import duty, to avoid paying the tax on watches not destined for the British market, Wilsdorf moved his main Swiss office from La Chaux de Fonds to Bienne, and expanded the function of the consolidated office to include checking all the watches he purchased from Aegler, whether they were bound for London or elsewhere, so that watches bound for countries other than Britain did not need to pass through London, and therefore did not pay the tax. For the time being the head office of Rolex remained in London.
Rolex watches continued to be made and cased in Switzerland, apart from gold watches (of all grades) that were destined for sale in Britain, and which therefore would be subject to the expensive import duty. Gold cases for watches to be sold in Britain during the period of high import duty were made by Dennison in Birmingham, England, to avoid the import duty. Silver watches, which attracted less tax because of their lower price, continued to be made and cased in Switzerland.
In 1919 Wilsdorf decided to relocate the headquarters of Rolex from London to Geneva. The same year also witnessed another major development in the history of Rolex when Wilsdorf and Davis gave nearly 15% of equity in their company to Herman Aegler. With this exchange, Aegler became the sole supplier of movements to Rolex and in exchange the company's name was changed to Aegler S.A. Rolex Watch Co.
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My Grandparents' Rolexes
In 1918 my grandfather purchased a pair of Rolex watches for himself and my grandmother. You can see them together in the photograph below, and then the dial, movement and inside case back of my grandfather's watch. The dials are very easy to read. My grandfather's watch in particular has a beautifully simple design; sharp black arabic numerals on a crisp white enamel background, the 12 being picked out in red. The hands are elegant and perfectly proportioned, the minute hand being a slender baton and the shorter hour hand a lunette style. My grandmothers watch has a silvered dial with Roman numerals, again the 12 (XII) is picked out in red, and the hands are the same design as on my grandfather's watch.
On the 13 ligne Rebberg movement of my grandfather's watch you can see that the plates and bridges have a beautiful engine turned perlage pattern. The small crown wheel is engraved “SWISS MADE” and the larger ratchet wheel “ROLEX 15 JEWELS”.
Inside the case back are, from the top, the sponsor's mark “W&D” in an oval shield with points top and bottom, then “.925” in an oval, the UK symbol for silvery purity of 92.5% or sterling silver, a mark that looks like an omega symbol on a cross in an oval shield, the London Assay Office town mark used on imported silver, and below these the date letter, a gothic “c” for 1918/1919. Underneath the British hallmarks are the Swiss hallmarks of a bear rampant and 0.935, the Swiss higher standard of silver until 1933. Either side of these are stamped “Rolex” and “ SWISS”.
The movement of my grandmother's watch is exactly the same as my grandfather's watch only smaller, with a 10½ ligne Rebberg movement. The inside back of the gold case is marked “Dennison Watch Case Co.”, the Birmingham watch case manufacturers. It has the “9” and “.375” hallmarks for 9 carat gold, the anchor used the Birmingham Assay Office on native British manufactured items, and a date letter “s”for 1917/1918. The Rebberg movement was evidently imported from Switzerland but cased in England, to avoid the high import duty mentioned above.
The presence of import hallmarks in the case of my grandfather's watch shows that it was cased in Switzerland before being imported, whereas the native British hallmarks in my grandmother's watch show that the movement was imported bare and then cased in England. The extra cost of the ad valorem duty of 33.⅓% on imported luxuries evidently did not make it worthwhile to use English silver cases, but it was worthwhile when for gold cases. There is much more about hallmarks and date letters on the pages beginning with my Casemarks page.
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The Rise of the Rolex Brand
In Britain there was a tradition that it was the name of the retailer that appeared on watches. Wilsdorf realised that as long as the retailers continued to put their names on the dial, they had control of what they purchased and sold, because they could put their name to any watch they chose. Although by having the movement and case branded with the Rolex name Wilsdorf could build up a reputation with the retailer, this would mean nothing to the customer who would rarely if ever look inside his watch. Wilsdorf was determined to produce the best wristwatches possible, believing that this was the key to success. He also realised that he would get better orders and more control over the wholesale price of his watches if he could build up demand so that customers would go into the shop and ask for, or better still insist on, a Rolex watch by name.
In addition to the various publicity events, such as obtaining the world's first chronometer certificates for his wristwatches, Wilsdorf began to push forward the Rolex brand. Initially he applied labels to the back of the watches, but this was not enough. So from 1921 he began to ship watches with the Rolex name printed on the dial. At this time watches were shipped in small boxes, each containing 6 watches. To start with only one watch in each box had the Rolex name on the dial, then later two of them, and slowly he increased the number of Rolex branded watches sold. However, this was too slow for Wilsdorf and in 1925 he started an intensive advertising campaign costing £12,000 each year. In 1925 Rolex registered the crown symbol as a trademark. Wilsdorf writes that the retailers gradually accepted that four, and then five out of every six watches were branded Rolex.
With the launch of the waterproof Rolex Oyster in late 1926, Wilsdorf was able to insist that all Oysters should have Rolex on the dial. Wilsdorf continued his advertising campaign in support of the increasing branding of his watches, culminating on November 24, 1927 when he took over the whole of the front page of the Daily Mail, at a cost of £1,600, with a full page advert for "The marvellous Rolex wristwatch - The World's best by every test" and stated that "All Good Jewellers throughout the British Empire stock Rolex watches". By his branding and advertising campaigns, Wilsdorf effectively turned the tables on the retailers: no longer would he have to approach retailers and ask them to stock his watches, customers would demand Rolex branded watches, and the retailers would have to come to him!
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Dust and water resistant cases
Being a perfectionist, attaining a class A precision certificate from Kew only spurred Wilsdorf on to addressing another shortcoming of the wrist watch: its susceptibility to dust and damp. In the wristwatch's unprotected position on the outside of the wrist, unlike a pocket watch, it was exposed to impacts, moisture, and dust. Shipments of wristwatches sent abroad were often found to have rusted by the time they arrived from exposure to dampness. Wilsdorf was not the first person to attempt to make a waterproof watch - many earlier watches are described on my page about waterproof watches - but he was by far the most commercially successful.
In the the Rolex Jubilee Vade Mecum Wilsdorf writes "To my technical assistants, my constant refrain was, from the earliest days: We must succeed in making a watch case so tight that our movements will be permanently guaranteed against damage caused by dust, perspiration, water, heat and cold. Only then will the perfect accuracy of the Rolex watch be secured."
With the end of the first world war (WW1) in 1918, global trade resumed and Rolex found that they were sending many watches to the far reaches of the British Empire. The humid tropical climate soon rusted the movements of watches in conventional cases, so a damp proof case was urgently required. In their book "The Best of Time: Rolex Wristwatches: An Unauthorized History", Jeffrey Hess and James Dowling note that Rolex produced a small series of watches using the one piece Borgel screw case in 1922. They remark that "Despite the small number of watches produced in this case style, it is a very important development in Rolex watch design. It was the first model produced by Rolex in which the case was specifically designed to give protection against some of the elements." These Borgel screw case Rolex watches were the start of a line of development which would culminate in 1926 in the Rolex Oyster.
In 1891, the Swiss watch case maker François Borgel (1856-1912) patented a case design where instead of having a hinged back cover allowing access to the movement, the normally separate case back and middle part were made in one piece. The movement was mounted in an externally threaded carrier ring, which is attached to the bezel and crystal, and the whole assembly screwed into the one-piece case from the front on a very fine thread. With careful manufacture and assembly the bezel could be made to screw down quite securely against the middle part of the case. The crown was held by a spring against the end of a tube carrying part of the split winding stem, creating a seal, and even the hole in the case for the push-pin for the hand setting mechanism was covered on the inside by a flat steel spring, so these Borgel cases are more waterproof than many people give them credit for. I have taken one (without its movement, just to be on the safe side) and held it under water for a few minutes and it didn't let in water. Not a dive watch maybe, but much better than the standard hinged snap back case of the time. You can read more about Borgel watches on my Borgel page.
To remove the movement of a Borgel cased watch, you first pull out spring loaded crown so that the winding stem is clear of the movement, and then the movement and bezel with the crystal unscrews out of the front of the case in one piece. Because of this, the method of setting the hands is unusual. The crown in its normal position winds the spring as usual, but obviously the pulled-out position is now used to release the movement. To allow setting of the hands, a pin just below the crown is pressed in and the crown then moves the hands. The picture shows a Borgel cased watch with the movement unscrewed from the case. You can see the screw thread on the movement, and the holes where the winding stem and pin-set engage with the movement.
Jean Finger Patent 89276
This case design has been attributed to a Francis Baumgartner, but this name is an error based on the conflation of François Borgel and Frédéric Baumgartner due to their common initials of of FB. The semi-hermetic case bears a strong resemblance to one patented in 1924 by Charles Rothen, an employee or associate of Borgel, which you can see on my Borgel Cases page. I have not found definitive evidence of the originator of the semi-hermetic case, it may well have been simply a development of the Rothen case.
Several companies used swing ring cases in the 1920s, including Omega, Longines and Rolex. However, they still were not sealed at the winding stem opening.
Rolex Hermetic. Image by kind permission
of and © Anthony Green Antiques
The Double Case or Hermetic
In January 1921 Jean Finger, a watch case maker of Longeau, Berne, Switzerland, was granted Swiss patent number CH 89276 for a " Montre à remontoire avec boitier protecteur" literally "a watch with a protective box". The watch was placed inside a larger case which had a screw-down bezel, forming an hermetic seal and totally protecting the watch within. Once the bezel was unscrewed, the flipped out on a hinge to allow the hands to be set and the movement wound.
Although this case achieved the desired waterproof effect, it had the major drawback that the bezel of the outer case had to be unscrewed every day so that the watch could be wound. Apart from being a nuisance to the owner, the case threads and the milling on the bezel wore quite quickly from this continuous use, so this was a far from ideal solution. However, despite the drawbacks a number of manufacturers including Zenith and Eberhard produced watches using this case design.
It appears that Wilsdorf must have liked the design and bought the rights to the patent, because he registered exactly the same case design on May 26 1922 under British patent GB 197208 "Improvements in and Relating to Watches". A Rolex "hermetic" watch using this case design was produced from 1924, and similar designs from other manufacturers disappeared. Some hermetic cases bear the words " Double Boitier Brevet 89276" (Double Case Patent 89276), a reference to the Jean Finger patent. Some cases bear the initials JF and these were actually made by Jean Finger.
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Rolex Oyster. Image by kind permission
of and © OldeTimers.com
The Rolex Oyster
In late 1926 Rolex launched on to the market a new watch with a waterproof screw-down crown and waterproof case. It was named the Rolex "Oyster" by Hans Wilsdorf because, like its namesake it could remain under water for an unlimited time without detriment.
To what extent was the Rolex Oyster a Rolex or Wilsdorf design? There had been many previous waterproof watches reaching back as far as the mid nineteenth century, as described on my page Waterproof watches, but none of these had gone on to commercial success. The Oyster case was almost certainly inspired by the 1903 Borgel 3 piece screw case which Rolex used in the 1920s, and he got the idea for the screw crown from Perregaux and Perret. But it was Wilsdorf who not pulled it all together and made it happen. When it was realised that the Perregaux and Perret screw crown design was essentially useless it would have been Wisldorf who cracked the whip and got his technicians to come up with a workable design. And in the end it was Wilsdorf the marketing genius who was prepared to invest so much on advertising Rolex that he created a watch brand from a name that didn't even exist until 1908, and then eclipsed all others in the popular imagination. Hans Wilsdorf was the restless genius who really propelled Rolex towards the heights it eventually reached - he must have been an interesting guy.
Registration of "Oyster" July 1926
Once he had a wristwatch unlike any other, Wilsdorf was determined to promote it in any way possible and embarked on an extensive and expensive advertising campaign.
On 7 October 1927, Mercedes Gleitze became, at her eighth attempt, the first British woman to swim the channel. She swam from France to England in 15 hours and 15 minutes. Because of a hoax claim (which was soon proven to be false) by Dr. Dorothy Cochrane Logan (using her professional name, Mona McLennan), to have swum the Channel on October 11th in the faster time of thirteen hours and ten minutes, Gleitze's own claim was cast into doubt. To silence the doubters, Gleitze decided to repeat her feat in what became known as "the vindication swim".
Recognizing a tremendous opportunity to demonstrate the durability of his "Oyster" watch, Wilsdorf offered a new Rolex Oyster watch to Miss Gleitze if she would carry the watch during her swim, to which she agreed. Although it has often been said that she wore the watch "strapped to her wrist", in fact she wore it on a ribbon around her neck. On 21 October at 4:21am Mercedes Gleitze once again entered the water at Cap Gris Nez. But this time the water was much colder, and she was unable to complete the crossing. At 2:45pm, after swimming for 10 hours and 24 minutes, she was pulled semi-conscious from the water some seven miles short of the English shore.
The Times, Oct 22, 1927
Although she did not complete the second crossing, a journalist for The Times of London wrote "Having regard to the general conditions, the endurance of Miss Gleitze surprised the doctors, journalists, and experts who were present, for it seemed unlikely that she would be able to withstand the cold for so long. It was a good performance." This silenced the doubters, and Mercedes Gleitze was hailed as a heroine.
As she sat in the boat, The Times' journalist made a discovery and reported it as follows: "Hanging round her neck by a ribbon on this swim, Miss Gleitze carried a small gold watch, which was found this evening to have kept good time throughout." When examined closely, the Oyster watch was found to be in perfect condition, dry inside and ticking away as if nothing had happened.
1930 Rolex advert in Punch
One month later, on 24th November 1927, Wilsdorf launched the Rolex Oyster watch in the United Kingdom as the focal point of a full front page Rolex advert in the Daily Mail, and the Rolex Oyster began its rise to fame.
Old Bond Street House
6-8, Old Bond Street
13th May 1930
I have now been using my Rolex Watch for some little while, and it is keeping perfect time under somewhat strenuous conditions.
I was wearing it on the occasion of the J.C.C. Double 12 Hours Race on Friday and Saturday last, and the vibration which this watch had to withstand during this long period has not upset its time-keeping properties in the least.
I would like to congratulate you on having produced a very first-class Watch, suitable for really rough treatment.
Yours faithfully, Malcolm Campbell
Wilsdorf also co-opted various sporting personalities into endorsing the Oyster. This advert appeared in Punch on the 18 June 1930. In it is reproduced a letter from Captain Malcolm Campbell (he was knighted as Sir Malcolm Campbell in 1931).
Note that although Campbell says that the watch is suitable for really rough treatment this was still before the widespread use of shock protection jewel settingsfor the balance staff pivots, so a sharp blow could, and still can, break the balance staff pivots on one of these watches, so don't take Campbell too literally.
The investment of a watch in Miss Gleitze's attempt proved a typically shrewd move by Wilsdorf, and Rolex were still using the event in adverts into the 1950s. The advert below left from Punch in August 1950 states that the Rolex Oyster was the first waterproof wristwatch in the world, which is not strictly true, there were other waterproof wristwatches made before the Rolex Oyster, but it was the first that was advertised to a mass audience through an extensive advertising campaign, Wilsdorf's forté.
The two features that made the Rolex Oyster waterproof were the screw down crown and the waterproof case. Let's have a look at each of these in detail in the following two sections.
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The Rolex screw down crown
Perregaux & Perret Patent 114948
On October 30th 1925 in La Chaux de Fonds, Paul Perregaux and Georges Perret, registered Swiss patent No. 114948 for a moisture proof winding system, where the crown was screwed down to create a waterproof seal. This patent was published on 17th May 1926. There seems to be nothing known about these two individuals, described variously as watchmakers and prototype makers.
1929 Oyster Case Back
Image by permission © OldeTimers.com
When Wilsdorf saw this patent, he must have thought he had found the solution he had been searching for. He bought all rights to the patent and had it assigned to him, and then registered it as British patent No. 260554 on 1 September 1926. The British patent was published on 21 April 1927. He also patented it in Germany No. 443386, and the United States No. 1,661,232. You can see the Swiss and British patents referenced in this 1929 Oyster case back, where Wilsdorf has used a bit of "artistic licence" to show the original Swiss registration date of 1925 alongside the British patent number.
However, although the Perregaux and Perret patent is often referred to as the patent that made the waterproof Oyster possible, not least by Rolex as can be seen from the Oyster case back pictured, it has some serious practical problems which prevented Wilsdorf from putting it into production.
The way the Perregaux and Perret design works is as follows: the stem 4 and socket 6 are screwed together so that they are effectively one piece. The crown 8 is connected to the stem and socket by the two screws 9 and 10. These screws can slide in the longitudinal grooves 11 and 12. This permits the crown to move axially with respect to the stem and socket, screws 9 and 10 sliding in the grooves as shown in the difference between figure 1 and figure 2. But the screws ensure that the stem and socket are locked together rotationally: the stem must follow any rotation of the crown.
The screw thread on the tube 3 that projects from the case, and the corresponding thread on the inside of the crown are left handed. The reason for this is as follows: when the watch needs winding the crown is unscrewed clockwise, in the direction of winding. Once the watch is fully wound, and the hands set if required, then the crown is screwed back down anti-clockwise, against winding the ratchet.
This is quite clearly stated in the patent: "The present invention relates to improvements in keyless watches and more particularly to improvements in and connected with the winding mechanism of such watches and is concerned with improvements in that type of winder in which the winder is secured in a moisture proof manner to the pendant or equivalent by means of a left hand screw-thread on the winder engaging a left hand screw-thread on the pendant and then screwed down on the pendant compressing packing means. " (my bold emphasis)
The reason for the left hand thread is because once the watch is fully wound, the crown can no longer be turned clockwise as would be required by a right hand thread, so the thread must be left handed. The crown has to be screwed down in the direction allowed by the winding ratchet, which is anti-clockwise, or left handed, a very unnatural action!
There are some further undesirable consequences of this design. Once the watch is fully wound and the crown screwed down, the crown cannot be unscrewed until the watch has run down somewhat, because the action of unscrewing the crown also winds the watch, and if it is already fully wound it cannot be wound any further without breaking. So if the owner winds the watch fully, screws the crown down, and then realises that the hands need setting, he is stuck for an hour or two!
Wilsdorf Patent CH 120848
Another poor featureis that the waterproof seal is formed by the gasket 16 against the case, which is in a very exposed position, and would not have lasted long given the gasket materials available in the 1920s; leather, cork or felt.
A better design: CH 120848
The Perregaux and Perret design was impractical to say the least, requiring a fair amount of education and care on the part of the customer if disaster was to be avoided. Wilsdorf must have soon realised that this design was not suitable to be released to the public. He put on his thinking cap, or more likely got his "technical assistants" working on it, and by October 1926 they had come up with an improved design. The patent for this was registered by Wilsdorf on 18 October 1926 as Swiss patent CH 120848, a figure from which is reproduced here.
The clever bit of CH 120848 was that a dog clutch was incorporated into the joint between the stem and the crown, so that the crown could rotate freely while being screwed down and unscrewed from the case, but it became rotationally locked to the stem by the dog clutch when it was clear of the threaded tube on the watch case. This meant that the crown could be could be unscrewed at any time to wind the watch or set the hands, and then screwed down onto the case by a right hand thread that would be familiar to any customer.
Referring to the FIG. 1 from the patent, cylinder 6 is fixed into the crown by a screw thread. The base of this cylinder has a square hole 9 in it which I have ringed in red. The plug 10 screws on to the end of the winding stem, and has a circular flange 11 to centre it within the cylinder 6 and support the spring 13, and a square section 12 at its base which I have also ringed in red.
When the crown is unscrewed from the threaded tube 2, which is fixed into the case wall, it is and pushed away from the case by the spring and the square section 12 on the stem end plug drops into the square hole 9 in the base of cylinder 6, and the stem and crown are then locked together rotationally as shown in FIG. 2.
As soon as the crown is pushed back towards the case to screw it down, the square section on the stem pulls free of the square hole in the base of the cylinder, and the crown is free to rotate and be screwed down without turning the stem.
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The waterproof Oyster case
1929 Oyster Case Back
Image by permission © OldeTimers.com
For the Rolex Oyster a new waterproof case was designed and patented. If you look in the case back of an early Rolex Oyster such as the one pictured here you will see four patents listed: two "Great Britain Patents" 260554/1925 and 274789, and below them two "Swiss Patents" 114948 and 120851. These are a British and a Swiss patent for each of two inventions. The first British / Swiss pair (260554 / 114948) were for the waterproof screw down crown; the second pair (274789 / 120851) were for the waterproof Oyster case.
An interesting feature of the patent for the case is that it begins by saying that the invention refers to a shaped or "forme" watch case (i.e., different from the usual round or circular form). The patent goes on to illustrate and describe an octagonal case and the means by which this case can be made watertight.
Referring to the cross section below, the movement is held in an externally threaded carrier ring 5, which passes through the centre of the shaped case. The front bezel and case back, both numbered 11 in the drawing, screw onto the external threads of this carrier ring, rotating in opposite directions and clamping the middle part of the case between them to form the water tight seal.
Oyster case cross section
The design of the threaded carrier ring is so reminiscent of the screw cases designed by François Borgel that it is not surprising that many people think the Borgel company, then owned by the Taubert family, must have been involved in the design, but no link has yet been proven. However, it is known that that the Borgel company supplied Rolex with three piece 1903 Borgel patent screw cases in the 1920s, so it appears that the Oyster case was based on this design. Wilsdorf was working on the Rolex Oyster in the years before 1926, and the Borgel company was taken over by the Taubert family in 1924, so perhaps Wilsdorf didn't want to approach what was essentially a new and untested company. There is also the strong possibility that the Tauberts would have wanted the Borgel trademark of the initials FB over a Geneva key to appear on any cases they made, which wouldn't have suited Wilsdorf.
The threaded Oyster case backs were milled with small radial grooves like the edge of a coin to provide the grip needed to tighten and release them by hand, the same as François Borgel had been using on the bezels of his screw cases since 1891. To get a tighter seal than possible by hand tightening in 1926 Wilsdorf designed a tool that engaged with the millings and enabled greater torque to be applied than by hand. On 3October 1929 Wilsdorf applied for a patent for this tool, which was published on 16 January 1931 under N° CH 143449. The millings on the case backs of modern Rolex watches, and the case openers used today, derive from these early designs.
Who made the cases of the first Rolex Oysters?
Rolex do not reveal information such as the identity of the case maker who supplied the cases for the first Rolex Oysters. However, beginning in the mid 1920s Swiss watch cases of gold and platinum had to be marked to identify the case maker. These marks, called Poinçons de Maître, were very small, and the identity of the maker was encoded, so they are not well known. I am not going to go into this in detail here, you can find more about it on my page about Swiss hallmarks, but the important point is that these marks can in principle be read to identify the maker of a watch case. The problem is that they are so small they usually can't be read from photographs, at least not at the resolution commonly published on the internet.
Thanks to Crispin at Oldetimers I was able to examine nine high resolution pictures of early Oyster cases. From these I was able to date the cases from the date letter of the British import hallmarks, all impressed by the Glasgow Assay Office, and to read the symbols and numbers of the Poinçons de Maître (PdM) - see the table here. The Glasgow date letter was changed on 1 July each year, so each letter represents parts of two calendar years.
Transfer of patent 114948
The cases cover a ten year period from 1927 to 1937 and all, except the last, have the Poinçon de Maître of a hammer head bearing the number 136. This shows that they were made by the company of C. R. Spillmann SA of La Chaux de Fonds, later Chêne-Bourg and this shows that C. R. Spillmann SA were the makers of the first Rolex Oyster cases.
The company C.R. Spillmann was involved in the acquisition by Wilsdorf and Rolex of the rights to the Perregaux and Perret patent for the screw crown, CH 114948.
The record from La Fédération Horlogère Suisse shown here records the transfer in October 1925 of the rights to the Perregaux and Perret patent CH 114948, first to C.R. Spillmann et Cie,, and then onwards from Spillmann to Hans Wilsdorf. Together with the Poinçons de Maître from the Oyster cases dating back to 1927 this shows that the Spillmann company not only made the waterproof cases of the first Rolex Oysters but was heavily involved in the design of, and in fact probably were the actual designers of, the waterproof case.
The company of C.R. Spillmann SA were listed as makers of gold watch case in La Chaux de Fonds. An obituary in La Fédération Horlogère Suisse recorded that Charles-Rodolphe Spillmann died on September 7th 1938. He was the founder and managing director of the company. He was also a founder and member of the executive committee of the Society of Swiss watch case manufacturers.
The address given in Spillmann's obituary was La Chaux-de-Fonds, but the 1934 list of PdM gives the company address as Chêne-Bourg. I think that the company of C.R. Spillmann had its headquarters in La Chaux-de-Fonds, the building is still there listed as a Swiss heritage site of national significance, and a factory in Chêne-Bourg.
The CR Spillmann SA Poinçon de Maître was cancelled on 5/4/1988. I am not sure whether the company was dissolved or taken over.
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The self winding Rolex Perpetual
Now that the problem of water-proofing had been solved, there was just one small remaining issue; namely, that the owner had to unscrew the crown each day in order to wind the watch. There were two side effects of this; (1) sooner or later the owner would forget to screw the crown down tightly again and the watch would no longer be hermetically sealed, and (2)in time the waterproof seals or the threads would wear out, and the same result ensue. This was solved by Rolex in 1931, with the introduction of the "Perpetual" self-winding movement.
The concept of a self-winding watch had first been introduced in 1770 by the Swiss watchmaker Abraham-Louis Perrelet for pocket watches. It worked on the same principle as a pedometer using an oscillating weight inside the watch that moved up and down as the owner walked, which through a set of gears wound the mainspring. Perrelet sold some of his watches to the Parisian clock and watchmaker Abraham-Louis Bréguet who improved the mechanism in his own version, calling his watches "perpetuelles"; the French word for perpetual, and possibly the source of Rolex's name for its automatic movements.
1950 Rolex advert in Punch
The first self winding wristwatch was invented in 1923 by a watch repairer from the Isle of Man named John Harwood. He took out a UK patent with his financial backer, Harry Cutts from Cheshire, on 7 July 1923, and a corresponding Swiss patent on 16 October 1923. The Harwood system used a semi circular weight that pivoted at the centre of the movement and swung through a 300 degree arc as the wearer moved his wrist or arm, and through a train of gears wound the mainspring. This was called a "bumper" design because the weight ran into a spring bumper at the end of its 300 degree travel, which the wearer could feel. When fully wound, the watch would run for 12 hours. It did not have a conventional stem winder, so the hands were moved manually by rotating a bezel around the face of the watch.
They formed the Harwood Self-Winding Watch Company and commissioned the Swiss firms Fortis and A. Schild to make the watches using the Adolf Schild Calibre Cal. 350 as the base movement. The watches went on sale in 1928. They were not a runaway success in the market, and only some 30,000 were made in total. However, the presence of the patent meant that from 1923 no one else could develop a similar or improved version, so progress was essentially halted at a time when the wristwatch was becoming more and more popular. The Harwood company collapsed in 1931 during the Great Depression and, although the patent still existed, there was no one to exercise it so other companies were free to develop their own versions.
Emile Borer, son in law of the Aegler family and head of research and development at the Rolex Bienne factory, took up the Harwood design and used it as the basis for the "auto rotor" of the Rolex caliber 620 Oyster Perpetual. He improved the design so that the centrally mounted semi-circular weight became a rotor which could rotate smoothly through a full 360 degrees and was able to turn both clockwise and counter clockwise, rather than running the 300 degrees and then hitting the bumpers of the Harwood design. This improved its performance, durability, and feel for the wearer, although it only actually wound in one direction. The Rolex version also increased the amount of energy stored in the mainspring, allowing it to run autonomously for up to 35 hours. Felsa introduced the patented 410 calibre "Bidynator" (bi-directional winding) in 1942; Rolex did not produce a bi-directional automatic winding movement until 1950 with the calibre 1030.
As a result of automatic winding it was no longer necessary to manually wind the watch every day, and the crown was used solely to set the time. As this did not require doing often, due to the accuracy of the watch, the waterproof seal was only disturbed occasionally and there was much less likelihood of wear or forgetting to screw the crown down. Consequently, Rolex Oyster Perpetual watches were now not only accurate but also durable. The automatically wound watch was even more accurate than the hand wound version because the tension put on the mainspring by constant winding whilst the watch was worn was more even than that provided by winding once a day.
In another marketing coup, in 1935 a Rolex Oyster went over 300 miles per hour on the wrist of Sir Malcolm Campbell as he set the world land-speed record in his race car at Salt Lake Flats.
Rolexes with calendars: the Datejust
In 1945, Rolex recorded another important patent. Watches had been fitted with calendar indications before using an extra hand to point to a circular calendar, which sometimes made the dial cluttered with hands and difficult to read. The Rolex design had a small aperture window added to the dial at the 3 o'clock position, and a disc with the date numbers under the dial was moved on at midnight by the mechanism so that the watch showed the date as well as the time. This model was introduced as the "Datejust" and it became an immediate best-seller.
It was followed in the early 1950s by the " President" - a man's wristwatch that has a window at 12 o'clock which displays the day of the week. Still not quite as good as the 1901 Goldsmiths watch we met on the history page, with its perpetual calendar showing day, date and month, and the moon phase dial, but not bad for a wristwatch!