High Speed Horology: A Greubel Forsey Tourbillon 24 Secondes Contemporaine

The tourbillon began life as a somewhat obscure and extremely expensive attempt to cope with the basic problem of variation in rate between positions, in mechanical timepieces. The rationale Breguet outlined in his patent also noted that the tourbillon was intended to help ensure even distribution of lubricant, but its primary purpose has generally been to address the fact that a mechanical watch will tend to run slightly faster or slower, depending on its physical orientation with respect to gravity. The tourbillon was originally developed by Breguet for use in pocket watches (there were no wristwatches in 1801, the year of his original patent) and so the tourbillon was designed to rotate in the vertical plane of a pocket watch, producing a single average rate for all the vertical positions. As George Daniels says in “Watchmaking,” you have only to adjust the flat positions to match that single average rate and you should, theoretically, have a perfect timekeeper.

However, the problem becomes more complicated (and it was pretty complicated already) when the wristwatch came along. The first attempt to put a tourbillon into a wristwatch was made in 1930, when Ernest Lipmann Fréres (later known as LIP) constructed a tonneau shaped tourbillon just 28mm x 18 mm (the movement is shown on page 265 of Reîhard Meis’ “Das Tourbillon.”) In subsequent decades Omega would produce some prototype tourbillon movements and Patek Philippe famously produced a small number of one-off tourbillon movements for the observatory chronometry competitions, although these were all built on the same basic design used by Breguet (the tourbillon rotating in the same plane as the movement plate).

The first known instance of constructing a tourbillon with an inclined balance, is a pocket watch attributed to A.H. Potter, an American watchmaker in, believe it or not, 1860. The rationale for putting the balance at an angle to the plane of the movement plate was that better chronometric results might be obtained if the watch were constructed so that the balance was essentially never in either a completely vertical or completely horizontal position, when the differences in rate would be the most extreme. The natural next development was the multi-axis tourbillon, the first of which was patented by Anthony Randall in 1977, and which was first constructed for a carriage clock by Richard Good in 1978. In 2004, the first multi-axis tourbillon wristwatch was created by Thomas Prescher, and Greubel Forsey, who have more than any other company made multi-axis tourbillons their stock in trade, was founded the same year.

Since then, Greubel Forsey has produced a number of variations on multi-axis and inclined axis tourbillons, starting with their 2004 Double Tourbillon 30º. This watch has an inner and outer tourbillon cage; the outer cage rotates once every four minutes on the same plane as the movement plate, and the inner, which is inclined 30º from the plane of the plate, rotates once per minute.  In 2012, Greubel Forsey introduced another variation on the theme, which was the Tourbillon 24 Secondes Contemporain – a 24 second inclined tourbillon in which the balance is at an angle of 25º to the plate.

Any tourbillon which rotates faster than one minute is generally considered a high speed tourbillon and with the 24 Secondes Contemporain, the high speed is, as with the idea of an inclined or multi-axis tourbillon itself, intended to reduce to an absolute minimum the time spent in any of the most extreme positions. The high rotational speed offers significant theoretical chronometric benefits (Greubel Forsey won the first prize in precision in the tourbillon category at the now-defunct Concours de Chronométrie, in 2011, with the Double Tourbillon Technique) and the 24 Secondes Contemporaine was and is another example of GF conducting exotic experiments in tourbillon design as a way of squeezing the best possible performance out of Breguet’s original design.

The entire tourbillon system, including the speed of rotation, the degree of inclination, and the construction of the oscillator system, are designed with all the attributes of a high precision mechanical timekeeper. The large balance (10mm in diameter) is freesprung; the balance spring has a Phillips overcoil (this is a development of the Breguet overcoil, devised by Breguet to ensure that the balance pivots remain centered as the balance oscillates. A condition of isochronism, or the ability of a mechanical oscillator to keep the same rate regardless of amplitude, is that the center of rotation and the center of gravity of the oscillator should always coincide). The Phillips overcoil was developed in the 1860s by the physicist Edouard Phillips, who put the empirical nature of Breguet’s overcoil invention on a solid mathematical footing.

The tourbillon at first appears to be a flying tourbillon, although it’s not – the upper bridge is an arch of synthetic sapphire, which carries the jewel for the upper pivot of the tourbillon cage. Sapphire is also used for the hour and minute chapter ring and the dial side of the movement overall, has an incredible sense of almost architectural three dimensionality, which is a characteristic of many of Greubel Forsey’s watches.

The dial side of the watch is organized into two levels, with the lower level housing the inclined tourbillon and running seconds subdial, and the upper containing the power reserve indication. The movement is driven by two fast rotating barrels, coaxially stacked, with a 72 hour power reserve; one of the barrels has an automatic movement-type slipping bridle, to prevent excessive torque.

You will probably have noticed by now, something else for which Greubel Forsey is famous: the movement finishing is as close to flawless as anything you are ever likely to see anywhere in horology. Any discussion of Greubel Forsey’s finishing should be prefaced by noting that it is not an example of a pure French-Swiss movement finishing approach (as can be seen, for instance, in Philippe Dufour’s Simplicity watches). It is instead a hybrid, combining aspects of both traditional English hand-made pocket watch finishing, and the French-Swiss approach (Stephen Forsey is English and Robert Greubel is French (he grew up in Alsace).

English watchmakers in general did not use Geneva stripes, and as a rule, preferred a full plate or 3/4 plate construction and they also favored a thicker construction in general than their Swiss counterparts. Movement finishing was usually a fine grained, frosted gilt finish. The mainplate of this version of the 24 Secondes Contemporain has a titanium mainplate with German silver bridges, both with a frosted finish.

As with traditional English hand-made pocket watches, the beauty of this style isn’t so much in the overtly jewel-like finish found in Swiss hand finished watches; instead, the appeal is more austere but no less beautiful. The quality is however, unimpeachable, with sharp inner corners whose presence and distribution are appropriate to the movement architecture, as well as features like elaborately finished screws and flawless countersinks. The screw heads are miniature works of art; they are polished on top, with beveled and polished edges and flanks; the screw slots are beveled and the bevels, slot sides, and bottoms of the screw slots polished as well; all the work is done by hand and while the 24 Secondes Contemporaine is ingenious chronometrically, the quality of execution gives up nothing to the abstract cleverness of the movement design.

I’ll can never write about or look at a Greubel Forsey watch without remembering the first conversation I ever had with Stephen Forsey, a million years ago when he brought GF’s watches to New York for the first time. I was seated next to him at dinner, and he gave me, over apps, mains, dessert, and a lot of wine, one of the single best lectures I have ever heard from anyone anywhere on the theory and practice of the tourbillon as an aid to advancing chronometry. At the end of the dinner I asked him (I have repeated this story a million times, but repeating the same stories over and over is one of the privileges of age) whether or not such amazingly complex mechanisms really had a definite advantage over an ordinary tourbillon, or over a conventional watch. He laughed and said, “Well, Jack, the theory is sound; in practice it is always a struggle to gain more than you lose.”

The fascination for me to be found in Greubel Forsey is in the pursuit, however; there is an air of obsession about the founders’ ceaseless experimentation which, if you combine it with the incredibly painstaking work to be found in construction and finishing, makes Greubel Forsey’s watches like no others on Earth. Perfect precision is by definition impossible, whether you’re talking about mechanical watches or optical atomic clocks, but it is in our nature – in the best part of human nature – to pursue as far as possible a principle, even if you can never quite achieve it in practice. So much of luxury nowadays – in watchmaking as in anything else – gets uncomfortably closer and closer to defining itself by scarcity and price, rather than character and quality. It is therefore refreshing to see a watch like this, which is a reminder that the real definition of luxury is, “it costs whatever it costs, and it takes as long as it takes.”

For more on the history, theory, and practice of the tourbillon, check out our four part series, The Tourbillon Chronicles, starting with Part 1. 

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