Dear Forum Readers,
In appreciation of your favorable comments to my recent earlier technical posts I am pleased to share and re-post a now revised article which I originally wrote in 2006 about Perpetual Calendar mechanisms developed by IWC. *
Much has been written about the original IWC DaVinci Perpetual Calendar timepiece, ref. 3750, which, since introduced in the mid-1980’s, has been one of the longest and most successful model in the IWC line. The brain child of Kurt Klaus with the encouragement of the legendary Gunther Blumlein the technical structure of the mechanism of the calendar block was a stroke of genius never constructed before in the world of watchmaking. It eliminated individual case pushers to correct the calendar system and allowed the owner user to carefully synchronize his timepiece effortlessly.
The technical wonder of the perpetual calendar system under the hood was masterfully exposed early on by Walt Odets who had an excellent technical grasp combined with photographic skills to illustrate and dazzle collectors and others of this unique timepiece. His article, and recommended reading, can be found in the TZ library.
I'd like to focus my attention now, once again, to the technical innovations of the perpetual calendar mechanism found in the Ref. 5021 with its calibre C50611 which is a derivative of the DaVinci perpetual. The Ref. 5021 is a 44mm timepiece with different functions and features than the DaVinci. Although the perpetual system is essentially the same with control of the crown, there are striking noticeable differences in the new calibre perpetual assembly under the hood and only visible to watchmakers lucky enough to come in contact with them.
To accommodate the ref. 5021, engineers at IWC went back to the drawing board and reinvented the wheel so to speak. Not only is there a new double moon disc (subject matter discussed and found in the archives) but, among one of many innovations, the calendar mechanism now is held in place with three upper bridges instead of one full bridge found in the old DaVinci perpetuals.
The three bridges are decorated with a pearl finish, the decade and year discs are held secure with a center screw, and the century disc is held firmly from accidental rotations with a round ruby jewel mounted on a curved spring.
I cannot take direct credit for the upgraded perpetual calendar block assembly but I am pleased to say that my teacher/mentor Kurt Klaus was always available to me by phone and e-mail to receive several suggestions I proposed in modifying the earlier calendar block. Perhaps the much larger size required for the Big Pilot timepieces added to the necessity of a three-bridge construction versus one bridge covering all the wheels, gears, levers, and springs. However, as many of you know, IWC is one of a few watch companies which on an ongoing basis implement gradual modifications as they deem beneficial.
These innovations are not a subject of advertising by IWC since, in my opinion, they are not different in principle than the ongoing refinements made regularly by the master watchmakers on different calbres across the board. They are also not of any visible importance to an ordinary consumer. But to a watchmaker fortunate to be working on one of these small engines it is the difference between viewing/working on an automobile with a standard engine and that of one with a Ferrari or Rolls Royce. Well engineered, well thought out with clever refinements and technical changes.
Hats off to the IWC team!
Regards,
Jack Freedman
- I could not find my original article now in the IWC Forum archives and the earlier photos posted were of poor quality.
