Feature: How The World’s Smallest Movement Was Made
Maybe you’ve heard Jaeger-LeCoultre referred to as the watchmaker’s watchmaker, the company behind such greats as Patek Philippe, Audemars Piguet and Vacheron Constantin? It’s true, Jaeger-LeCoultre has supplied those masters—and many more besides—but you don’t get that kind of gig without already being a master yourself. This is the story of the calibre 101, and how Jaeger-LeCoultre became the watchmaker’s watchmaker.
The watchmaker hit the scene with a bang in 1833, when self-taught tinkerer Antoine LeCoultre decided he wanted to start himself a business. In the workshop owned by his family, where he and his father had studied and invented new metal alloys, LeCoultre forewent the opportunity to manufacturer the produce typically wrought by the machines there, choosing instead to make a machine of his own: a machine that made pinions.
A pinion is the shaft that holds a gear in place, without which it would simply fall out. But its job is so much more significant than that—a pinion that is not true will add friction to the movement, increasing inaccuracy, wear and power consumption.
In this burgeoning Swiss industry built on individuals crafting parts in their own homes during the cold winters, often poorly and inconsistently, LeCoultre set in motion not only the path for his own business, but also that of many other watchmakers for many centuries as well.
He was obsessed with accuracy, driven to further improve his own work to bring efficiency to his mechanisms. It was clear to him how much a Swiss movement was robbed of its performance by the quality of its components, which paled into comparison against their international counterparts.
Jaeger-LeCoultre was founded in 1833, Le Sentier, Le Chenit, Switzerland
But before LeCoultre could set about making better movements, he needed the tools not only to manufacture them, but measure them as well. He could attempt to work to as accurate a tolerance as he liked, but if he had no way to record that tolerance, it would have all been moot.
In 1844, LeCoultre finally realised his goal of measuring the immeasurable, creating a device he called the Millionometer, the first ever built that could accurately record a single micron—that’s a thousandth of a millimetre. Now, stop there for a minute and think about that: it’s not the machine itself that is most impressive, although it is indeed impressive—it’s the thinking behind it that made it possible in the first place.
It’s a classic chicken and egg scenario: if you can’t measure a micron, how do you build a device that can? The tolerances of such a thing would need to be at least as accurate of what it’s capable of measuring, but most likely they would need to be greater. But … with no way of measuring it, it’s a task bordering on the impossible, surely?
Not for Antoine LeCoultre. His understanding of metal and manufacture allowed him to build with the tolerances he needed, even though he was unable to measure them, and with the Millionometer created, he could pass that ability on to others as well. This was the start of the “Grande Maison”, LeCoultre’s original plan to become the greatest watchmaker in all of Switzerland.
Jaeger-LeCoultre was founded by Antoine LeCoultre
By 1888, the manufacturer LeCoultre had become everything Antoine had dreamed of. Employing over 500 staff, winner of the Universal Exhibition gold medal for contributions to the modern age, supplier to Queen Victoria herself, it was a business thriving. The company had accrued over 300 calibres to its name, with over half of them complications.
Furthermore, Antoine had, as his years grew in number, passed the keys to his legacy to his son, Elie, and Elie to his son Jacques-David, who had become fast friends with another manufacturer of mechanical instrumentation: Edmond Jaeger. Jaeger had become famous for supplying watches to the French Navy, and hearing of this rising star in the Vallée de Joux, LeCoultre, had conjured a challenge for this master of precision.
Jaeger had a plan, quite literally, of a movement that would be the thinnest ever made. But he also had a problem—he, and no one else it seemed, had the capability to actually make the damn thing. Up until then it was purely theoretical, a “what if” that was predisposed to a technological breakthrough in order to be physically realised.
But there was one company that might manage it, a company he’d heard mentioned with incredulity and wonder, that had earned the favour of the Queen of England. And so Jaeger wrote a letter to LeCoultre, proposing a challenge: build his movement, and his company and all the valuable contracts he had amassed, would be LeCoultre’s.
The Jaeger-LeCoultre calibre 101 is the world’s smallest watch movement
LeCoultre smashed it, for want of a better term, turning what was once just lines on a page into the calibre 145, a movement just 1.38mm thick and a challenger for the very thinnest still to this day. But what made the calibre 145 impressive wasn’t just its impossible thickness, or rather lack of it, but its performance. This was 1907, when movements twice as thick struggled to keep accurate time or reliable power reserve. The calibre 145 was actually usable, consistent, dependable. Jaeger was true to his word, and so Jaeger-LeCoultre was born.
Far from being the end, this was just the beginning. With Jaeger’s mind for problem solving and LeCoultre’s knowledge in metalworking and precision, the two men set themselves a new challenge, not just to make the thinnest movement, but the smallest. Here the problem grew tenfold, as with an ultra-thin movement, the design problem was quite straightforwardly solved by spreading the components apart and making them as thin as can be; the challenge there was almost entirely LeCoultre’s.
But for the smallest movement in the world, there could be no design tricks. Together, Jaeger and LeCoultre would have to embark on a journey of revolution, technical achievement, and a concept that would push them harder than they’d ever been pushed before. It would be, for them, the defining moment of Jaeger-LeCoultre.
But the real challenge still lay ahead: to design and build the world’s smallest movement, the calibre 101.
Although Edmond Jaeger had joined Jacques-David LeCoultre to form the Jaeger-LeCoultre watch company, Jaeger’s other concerns were still thriving. One of those surrounded the growing automotive industry, in the design, manufacture and supply of dash instruments like tachometers and speedometers.
By the middle of the 20th century, Jaeger supplied instruments to no less than Citroën, Panhard, Renault, Bugatti, Delage, Aston Martin, Triumph, Rover, Vauxhall and Bentley, as well as working in partnership with suppliers to Ferrari, Fiat and Alfa Romeo. But, unfortunately, Edmond Jaeger would not get to see this incredible success himself, because he had fallen gravely ill.
It was a critical time for Jaeger-LeCoultre, having signed an exclusive deal to provide Cartier with miniaturised movements for its jewellery watches for the next fifteen years. The quest for the smallest movement in the world was no longer just a challenge between friends—it would decide the fate of the company altogether.
The company Jaeger, despite Edmond Jaeger’s ill health, had to go on. Jaeger and co-founder Edmond Audemars—a distant cousin of Audemars Piguet co-founder Jules Louis Audemars, record-breaking aviator and the first to fly from Paris to Berlin, and beneficiary of pioneering World War 1 pilot Roland Garros’ will—then decided to appoint one Henri Rodanet as Technical Director of Jaeger.
The Jaeger-LeCoultre calibre 101 is the world’s smallest watch movement
Rodanet came from a line of Parisian watchmakers, and was a man plagued by misery. His father died when he was four, his mother when he was eight, and one of his sisters when he was nine. The remainder of his family moved in with their uncle, a watchmaker, who saw in Rodanet a talent and enrolled him in watchmaking school. His flair was quickly spotted by Edmond Jaeger, who brought him into the fold, and soon Rodanet was promoted into management.
But World War 1 struck, and Rodanet was mobilised onto the front line as a British Army interpreter. Yet despite the ongoing war, he found time to continue with his designs, making notes and penning sketches whenever he could, developing special instruments for the Allied effort. He alone would amass over 500 patents.
Wartime instrumentation was not the only thing on Rodanet’s mind, however, as the contract with Cartier loomed. On his return from the front, he received his promotion to Technical Director, and was tasked with the challenge of saving not only the reputation of the newly formed Jaeger-LeCoultre, but the business itself.
Rodanet put his technical nous to work, distilling the very essence of the mechanical movement and reassembling it in his mind. He knew that if he wanted to retain the accuracy for which LeCoultre was famous, the balance wheel of the watch, its beating heart, could not be shrunk—at least, not with the technology they possessed at the time. This one component was the seemingly insurmountable wall placed in front of him, the limitation that meant a traditional movement could shrink no further. But he wasn’t to design a traditional movement—he had a better idea.
The Jaeger-LeCoultre calibre 101 is 14mm in length, 4.8mm in width and 3.4mm thick
The idea took Rodanet several years to develop, working with the best minds at Jaeger-LeCoultre to push material technology to its maximum. What he proposed was unlike anything ever seen before, and its realisation was not going to happen overnight. A basic mechanical movement is typically made up of the following: a winding mechanism to add power, a mainspring to store it, a gear train to subdivide that power into hours and minutes and feed it to the hands, and an escapement to control the unwinding mainspring and regulate its power.
These components are usually seated along a single plane, one after the other, to ensure the movement is as thin as possible, maximising the width of the watch’s display to fit it all in. But Jacques-David LeCoultre had demonstrated with his advanced manufacturing techniques that the construction of a movement need no longer be determined by the constraints of thickness.
So, here was Rodanet’s idea: take the escapement and the winding mechanism and seat them side-by-side, not too dissimilarly to a traditional movement, but then bundle up the mainspring and the gear train and seat them directly underneath on an entirely new level. Now the movement could be as wide as just the balance wheel, and thanks to the technical achievements of the company’s manufacturing abilities, it could remain at a reasonable thickness as well.
This new movement, called the Duoplan, was the first to offer the performance of a larger movement in a small package. So proud were Jaeger-LeCoultre of this mechanism that, for just an additional two percent over the asking price, customers could purchase a comprehensive warranty that covered not just manufacturing defects, but water damage and even theft!
The Jaeger-LeCoultre calibre 101 can be found within the 101 Feuille bracelet and 101 Ring
A success for Jaeger-LeCoultre, the Duoplan revolutionised miniature watchmaking—but Rodanet knew there was more to come. Successively he developed iteration after iteration, rearranging the components, challenging the manufacture, finding every last micron of wasted space and eliminating it. There were four iterations in total, with the fourth and final, released in 1929, the smallest Duoplan of all: the calibre 101.
At just 14mm in length, 4.8mm in width and a scarcely believable 3.4mm thick, the calibre 101 became—and still is—the smallest mechanical movement ever made. With individual components weighing in the tenths of milligrams, the total weight is barely a single gram. Yet thanks to the combined expertise of companies Jaeger and LeCoultre, this tiny device still operates at a thoroughly contemporary 21,600 beats per hour, delivering the accuracy and usability expected of this prestigious organisation.
And there are no two examples of this record-breaking movement alike. For the calibre 101 to work, every single one if its ninety-eight components must be custom built, unique for every example. It’s this dedication to extreme performance that makes watches like the 101 Feuille bracelet, similar to the one worn by Queen Elizabeth II during her coronation, and the incredible 101 Ring to become possible. It was a rare moment of collaborating genius that has never been replicated since.
So now when you hear Jaeger-LeCoultre referred to as the watchmaker’s watchmaker, you’ll have a better understanding of how this incredible company came to earn that incredible reputation, how a meeting of minds and the thrill of a challenge brought the future of the watchmaking industry closer than ever before. The calibre 101 is not just a movement—it’s a line in the sand, the moment when excellent became exceptional, but most of all, an emblem of what can be achieved when we work together.
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Looking for a Jaeger-LeCoultre watch? Click here to shop now
