Some parts in a mechanical watch are so tiny and vulnerable that gravity disorients them, causing accuracy fluctuations depending on the position in which the watch is kept.
A tourbillon (pronounced “TOUR-bee-yon”) defies gravity and provides greater precision in the timekeeping of a mechanical watch by protecting those parts.
This high complication remains one of the most difficult and complex movements to master.
WHAT IS A TOURBILLON
The most precious complication
Historically, tourbillons have commanded top prices and were out of reach of all but the extremely wealthy. Very few watch houses have the time and experience to produce tourbillon watches, driving up prices even higher.
Watch houses usually produce a few dozen pieces of tourbillon watches each year, as only the most skilled watchmakers are capable of making the handcrafted movement. Considered one of the most complex watch complications, tourbillons are prized for their engineering and design principles.
The higher price is attributable to the complexity of the tourbillon mechanism, which is created within extremely tight mechanical tolerances with specialized tooling. Crafting a tourbillon requires more parts and time than in other movements. Dedicated tools and machinery are required to manufacture a tourbillon as well as special lightweight and durable metals.
HOW DOES A TOURBILLON WORK?
To counter the effects of gravity and other forces that affect the accuracy of clocks and watches Abraham-Louis Breguet invented in 1795, a tourbillon. It was originally designed to eliminate errors of rate in pocket watches, which were kept in vertical positions for long periods of time. This was leading to deviations in timekeeping due to friction conditions caused by gravity either accelerating or decelerating the vibrations of the balance. Breguet’s solution was to balance out all differences of position with a small “clock within a clock”. He did so by mounting the rate determinative components – balance, balance spring and escapement – in a delicate lightweight carriage which rotated on its own axis once every sixty seconds. In this manner, fractions of a second lost during the first 30 seconds were regained during the next 30 seconds so that the negative effects of gravity were neutralized, allowing many watches to attain chronometer-like accuracy.
It is critical that energy expenditure be at a minimum as the same energy from the mainspring to power the gears is also needed to move the tourbillon. Any instability or disturbance in this energy flow will decrease the accuracy of the watch. Even to adjust the tourbillon movement requires specialists who have to disassemble and reassemble the tourbillon to regulate the balance.
The movement’s mesmerizing rotations is the reason Breguet named his device a tourbillon – meaning “whirlwind” in French.
To this day, the complex construction and exacting precision required to create a tourbillion remains a specialty of the most gifted watchmakers. Two hundred years after the invention of the tourbillon, even today’s high technology manufacturing methods and precise machinery combined with innovative materials cannot overcome the negative effects of gravity, upholding the tourbillon’s status as a relevant and fascinating complication.