Watches in Depth - The Tourbillon ¶
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When it comes to complications, the tourbillon is the top tier of the watchmaker’s art. It is one of the most difficult complications to execute, one of the most expensive to buy, and one of the most superfluous in function. Tourbillons have had a sort of renaissance in the last 20 years, with ever more exotic and exponentially more complex variants, but the basic principle dates back to the 18th century when Abraham Louis Breguet was looking for a way to beat gravity.
At its most basic, a tourbillon is a rotating carousel that houses the balance wheel of a mechanical movement. The balance is thus in constant, steady rotation. The principle behind this is to reduce positional errors in the balance assembly. When a watch is shifted into different positions, the swing of the balance is affected by gravity. This causes subtle but measurable changes in the accuracy of the timekeeping. By putting the balance into constant rotation one plane of variation is eliminated (in theory).
The tourbillon was originally developed by Abraham Louis Breguet in 1795 as a way to compensate for positional variation in pocketwatches and carriage clocks. As a pocketwatch is usually held upright in a coat pocket, the tourbillon compensates for the effect of gravity in the up-down position (as opposed to flat on the back or dial). Breguet was one of the great innovators of early watchmaking, producing highly complicated pieces (including the legendary Marie Antoinette pocketwatch) and developing significant advances in timekeeping technology. Unfortunately Breguet was notorious for not keeping records or plans of his work, so these early tourbillons are shrouded in a bit of mystery. Supposedly the first was designed for Napoleon Bonaparte's personal carriage clock A few pocketwatches were produced by Breguet for special orders. It’s not even known if they performed much better than a standard, high quality movement.
Therein lies the oddity of the tourbillon – it is a highly complex system that doesn’t really do anything. In the early days of watchmaking positional variance was a major hurdle in achieving perfect accuracy; today a standard movement can be adjusted to run very accurately in multiple positions (the basis of chronometer testing) without the aid of something so complex and delicate as a tourbillon. As such, the tourbillon is more of a display of watchmaking talent than a useful complication. It’s become the standard measure of a high-end manufacture – if you make a tourbillon, you are one of the big boys in the Swiss industry.
A tourbillon is extremely difficult to produce and adjust. To get an idea of the complexity involved, you must recognize what is going on in the tourbillon “cage” – like any mechanical movement, power from the mainspring is being transmitted through the balance wheel to the gears of the movement. The balance regulates the flow of power from the mainspring to the rest of the movement. A tourbillon is taking the power, regulating it, then transferring it into the movement – all while rotating steadily within a tiny suspended assembly. A tourbillon cage rotates at a steady rate, measured in seconds or minutes. The most common is 1 minute (so the cage rotates once every 60 seconds, and doubles as a second indicator) but 30 second and multiple minute tourbillons exist as well. Generally a tourbillon will be exhibited through an opening on the dial, though some manufacturers (Panerai and Patek Philippe for example) only show it through the caseback. As it is such a complex and expensive complication, it makes sense that it should be proudly displayed on the dial for all to see.
How expensive is this complexity? Generally, a Swiss-made tourbillon will run at least 30 000 to 50 000$ (Alpina and Frederique Constant produce them in this price range), and can easily reach into the hundreds of thousands for something from a major manufacture with multiple complications. Don’t even ask about service costs, as only a small number of specialist watchmakers can adjust and fix tourbillons. Swiss tourbillons are the domain of the elite and a very visible display of watchmaking prowess. Now it should be noted that there are Chinese-made tourbillons that can clock in under 1000$, but the level of finishing is far removed from the Swiss examples. Chinese tourbillons are functional but rough around the edges, and rarely very accurate. As with everything in life, you get what you pay for. And one must beware of the numerous fake tourbillons out there that simply exhibit the balance wheel of the movement through the dial (normally called an open-heart but often described as tourbillons by unscrupulous sellers).
There are a variety of tourbillon designs on the market. A traditional design has a cage surrounding the assembly that houses the balance dead centre in the system, with solid bridges on both sides of the cage. The flying tourbillon appears to float in space by having a single mount on one side, rather than a bridge on each side. A carousel is a variation where the balance wheel is mounted off centre, so it orbits around the centre of the cage. After that, you get into multi-axis tourbillons and tourbillons with additional complications.
The craze for tourbillons only really began in the late 1990s. Up until that point there had not been many tourbillons designed or produced in any real numbers, just a few odd examples here and there from independent watchmakers as a demonstration of skill. Mechanical movements in general went on the decline in the 1970s following the quartz crisis; in the 1980s manufacturers changed tactics to promote mechanical movements as a luxury item. Soon brands began making ever more complicated models to stand out, with the demand for complications peaking in the late 1990s. It was during this period that the tourbillon found resurgence among major brands as a flagship complication.
By the 2000s the simple single-axis tourbillon was not enough to satisfy the growing demand for ever-more-complicated watches. Thus began the trend of double tourbillons (two tourbillons in a single movement, sometimes more) and the mesmerizing multi-axis tourbillon. Perhaps the most famous multi-axis tourbillon is the Jaeger LeCoultre Gyrotourbillon, which was released in 2005. The Gyrotourbillon is a dual-plane design, where a cage rotates within another rotating cage, both spinning at different rates. The effect is of a ball spinning through space. It is exponentially more complicated than a single-axis tourbillon and far more difficult to design and produce. Of course, someone had to one-up JLC – first were the multiple dual-axis tourbillons from Greubel-Forsey, and now the latest benchmark is the flying triple-axis tourbillon from independent maker Thomas Prescher. These movements are spectacularly complicated, and priced accordingly (about half a millon for the Prescher).
When it comes to haute-horlogerie complications, tourbillons are the king of the market. Every major brand worth their salt in high-end watchmaking will produce one. Every watch aficionado will lust after one, and be able to immediately spot one on the wrist from 100 yards. It is one of the most expensive and most spectacular complications available today, perhaps surpassed only by the minute repeater as a superfluous and exorbitant complication. For many people handling a tourbillon will be a once-in-a-lifetime experience; a tourbillon model production run for a brand almost never exceeds 100 examples, not mentioning the exceptional cost of purchasing such a watch. If you ever have the chance to hold a tourbillon, cherish the moment and study it carefully. It is one of the most mesmerizing and spectacularly complicated mechanical devices out there, and seeing one in person is something very special indeed. Concerns about gravity and accuracy be damned, a tourbillon is a cool complication no matter how useless it really is.