In November 2015, during Salon QP, Ian Skellern moderated a discussion between three independent watchmakers: Stephen Forsey; Bart Grönefeld; and Roger W Smith. What follows is a brief account of what was said, with thoughts, illustrations and links that some might find interesting / helpful.
Putting a tourbillon on a watch is like breaking your leg before a race; adding a remontoir d’egalité is like putting a plaster on it. F.P. Journe**
The tourbillon was patented by Abraham-Louis Breguet in June 1801 (or, more correctly, 7 Messidor, year IX), and had but a single aim: to reduce the effect of gravity on the escapement, by rotating the entire assembly once every minute.
Almost two hundred years later, when Roger Smith came to plan his first apprentice piece as part of his British Horological Institute course, he thought he might add one. “I’d never seen a tourbillon before” he admits, “only in [Dr George Daniels’] Watchmaking.” Daniels had previously said that adding a tourbillon to a movement was a wonderful way for the watchmaker to show off their skills. When Roger was planning his Pocket Watch No.2, he kept the tourbillon, adding a detent escapement and perpetual calendar. Indeed, the tourbillon appeared in No.3, as well.
Approximately ten years after Roger began work on Pocket Watch No.1 , Stephen Forsey and Robert Greubel were planning something completely different. They’d just returned from BaselWorld, and noted that a large number of brands had been exhibiting wristwatches with tourbillons. Seeing so many, similar approaches started them thinking about how they could improve watch timekeeping, as well as demonstrating the art / craft of the watchmaker. They also identified what they perceived as a problem with all tourbillons that were being made at the time: the seconds were almost impossible to read, therefore making these watches next to useless as precision timekeepers.
Ten years later, Bart and Tim Grönefeld were toying with similar ideas, but had also begun exploring the materials of watchmaking, seeking to make a steel tourbillon cage that could then be hardened, treated and tempered. Never ones to shy away from a challenge, they, like Roger, added a detent escapement. The result – the Parallax Tourbillon – was a hacking, flying tourbillon, where the cage is supported on only one side and which won the Grand Prix d’Horlogerie de Genève (GPHG) in 2014. In the case of the Parallax, the flying element was particularly difficult, as it pivots on ceramic ball bearings, which were particularly tricky to manufacture.
All three agree on one thing: the original aim of Breguet’s tourbillon was to increase accuracy. In a pocket watch, the action of gravity can be extreme; watches were often in pockets for extended lengths of time, and held in one plane. Indeed, at rest, a pocket watch was just as likely to be hung from a stand, further increasing the amount of time that the balance had to work against gravity. Even then, Breguet’s invention was slow to catch on: “look at the marine chronometers from Harrison, Arnold and Earnshaw, for example” says Smith, pointing out that these incredibly accurate timekeepers usually gimballed in one position, but rarely used tourbillons.
If I’m honest, the joy of the Parallax to me is the ability to read the seconds hand from virtually any angle, accurately and without error. And it is this that links the Grönefeld’s tourbillon back to Breguet’s (well, that and the rather fun cone-shaped power reserve, but that’s for another day).
While Tim, Bart, Robert and Stephen have all made something of a career from tourbillons, Roger freely admits that he’s still something of a novice. “My experience is fairly minimal” he says, “I’ve only made seven pieces to date.”
“I’m not a very technical person” Roger continues, before explaining that he has a “sense of what will work.” He tends to adjust the carriage or the inertia, but does’t really consider the forces at work. “I’d much rather make a non-tourbillon watch” he admits, “I like to keep things as simple as possible.”
Stephen and Bart are, of course, almost preternaturally technical, taking tourbillon development to levels that are probably hitherto unseen. In the 1970s, Stephen recalls, there was, in effect an end to research and development in mechanical movement making, and by the time he was studying at Hackney during the 80s, there was only a handful of ETA calibres left. When Stephen and Robert Forsey set up CompliTime in 2001, one of their key aims was to make a watch that was more accurate, generally making more gains than losses. This culminated in their Double Tourbillon 30° Technique winning the International Chronometry Competition (with a score of 915 out of a possible 1,000) points.
Greubel Forsey had previously entered in 2009, and hadn’t even placed. However, their Tourbillon 24 Seconds Vision was awarded the Aiguille d’Or, the top prize at the GPHG in 2015. The key difference between this and the Double Tourbillon is the size of the cage, which needed to be lighter because of the energy requirements of a faster rotation (the 24 Second tourbillon is rotation two and half times the speed of a sixty second tourbillon). Low density Avional (duralumin) was used to reduce the weight of the cage by two-thirds.
In the end, all three agree that while the tourbillon may have limited functionality in watches, and probably isn’t even a true complication, it’s up to the watch-buying public to decide.
** please see Ian Skellern’s comment below, for further information and context.
Disclosure: as a previous contributor to QP Magazine, I was provided with a Press Pass to SalonQP in 2015 and 2016. Tickets for daily access to this and other talks were c£20 per day.