Feature: How The World’s Thinnest Watch Was Made
Creating the world’s thinnest watch doesn’t happen overnight. It doesn’t happen in a month, or a year, or even a decade. It takes several lifetimes of expertise, development, successes, failures—all to get to this: the Piaget Altiplano Ultimate Concept. This watch is 2mm thick. Let’s find out how it was done.
From the perspective of an outsider, the challenges faced by a record holder are rarely observed. To you and me, the announcement of Piaget’s concept to build the world’s thinnest watch may have come out of the blue, but for Piaget itself, it’s been a journey of constant learning.
It’s an old brand, manufacturing watches and movements since 1874, and one of the advantages of making your own parts is the benefit of having complete control over the design. When you buy someone else’s movement, you’re stuck with what you get, you have to make compromises; when you build it yourself, you can push in whatever way you want to.
For Piaget, that was with slenderness. A wristwatch has, for much of its life, been a measure of a man’s decorum, his refinement—only from the 1970s did it become fashionable to wear one as a statement. Before that, it was a case of being neither seen nor heard, except only on the occasions where it was required.
At the 1957 Basel Fair, a crowd had formed around a small stand—I mean, all the stands were small back then, when it was a trade fair and not a circus—to chance a glimpse at what was to become the marvel of the entire event. At just 2mm, Piaget had created the thinnest calibre in the world, the 9P, a movement that was as pivotal back then as the change of Netflix from physical format to digital streaming.
Three years later, and with a bigger stand this time, Piaget did it again, announcing the calibre 12P, a 2.3mm movement that also somehow included automatic winding as well. How did they do it? By using a micro rotor, a smaller, more compact version of a full-size rotor that typically spans the entire diameter of a movement, Piaget was able to package this fully functioning mechanism into an extremely small space.
To establish just how incredible that movement was, compare it to the modern Altiplano 1205P. An automatic watch, featuring a micro rotor like the calibre 12P, it’s 0.7mm thicker than its older counterpart. Make no mistake, the 1205P is a staggeringly impressive movement and built upon many of the same principles—it’s just not as impressive as the one from the sixties.
But why? How did Piaget go from leading by a country mile, to failing to meet the standards of its own achievements? Between 1960 and 1980, the need for ultra-thin movements—and in fact any mechanical movement—all but disappeared. Quartz watches meant Piaget needed to find a new way to survive, and its increasingly popular jewellery was a great way to do it. Sadly, that meant progress on these physics-defying masterpieces hit a brick wall—and there it stayed for over half a century.
By 2014, Piaget’s 140th anniversary, the watchmaking scene had changed yet again. There was a hunger for mechanical complexity and ingenuity, like there had been back in the fifties and sixties. This reawakening came later than might perhaps be imagined, the turn of the millennium only just starting to pique the interest of modernist watchmakers like Urwerk and MB&F.
For a long time between, customers were happy to have anything going on inside their watches, but as awareness increased and the passion started to rekindle, manufacturers soon started to learn that a dressed-up ETA was no longer going to do the trick. This was a bit of a pain for companies that didn’t have the capability to manufacturer their own movements, and is a big part in why watch prices have gone up so much over the last few decades.
At Piaget HQ, meanwhile, a strokey beard meeting was had, and it was determined that this new interest in mechanical watches gave the brand the perfect opportunity to revive its pursuit of the ultra-thin watch. And it wasn’t to be just a thin calibre, but the thinnest calibre, one that took a complete, ground-up re-evaluation of how a watch is manufactured.
At 3.65mm, the Altiplano Ultimate 900P, the spiritual successor of that original 9P, may not sound too impressive—until it is revealed that this is the thickness not just of the movement, but the entire watch. And it’s no accident that the watch shares its name with the calibre inside, because for the first time ever, they were one and the same thing.
Let me explain. Where most watches have a movement housed inside a case that’s made up of a sandwich of the case back, case middle and bezel, the 900P did not. Instead it used a monobloc, a singular piece of metal that served all those functions—and one more. In the journey to making the thinnest watch ever, the watchmakers at Piaget realised something—the watch and the movement could become one homogenised part.
This meant that all the jewels and screw threads usually found in the baseplate—that is, the structural foundation of a movement—were manufactured straight into the case back instead. The rest of the calibre 900P was built straight on top of it, saving precious millimetres in the quest for thinness. Like the automatic rotor on the 12P, the dial was recessed into the movement, offering more space for the bridges. Wheels were shaved down to thicknesses less than a human hair. The mainspring barrel, attached only on one side, was suspended to eke out yet more slenderness. It’s all as thick as the thickest part—the balance wheel.
But Piaget wasn’t done yet. In 2017, to mark the 60th anniversary of the Altiplano, the 910P was created, an automatic version of the incredible 900P. At 4.3mm thick, the Altiplano Ultimate Automatic 910P smashed the record for the thinnest automatic watch using the same monobloc principle of the 900P, but now with a slender peripheral rotor winding the mainspring. Piaget was finally back where it belonged, making the thinnest watches ever made.
But this was still not enough. There were still microns to spare, wheels to shave, springs to thin. The challenges to do so, however, were far greater than the watchmakers at Piaget could have ever foreseen. In pursuit of the dream of making an entire watch as thin as that 1957 calibre 9P, the team went through hell and back. It very nearly didn’t happen on multiple occasions, demanding the utmost expertise from every single person on the project.
It all started at SIHH in 2014, after the successful release of the Altiplano 900P, then the world’s thinnest watch, when one of the marketing team joked with the technical team that they “should make a thinner one for next year.” The comment, in passing, did its intended job of winding up the people who’d worked so hard on making the 900P—but it also did something else, sowing a seed of thought in their minds. What if they could make a watch even thinner?
You can imagine how that silly little comment got under the skin of the people whose job it had been for the past few years to engineer the successor to the 1957 calibre 9P. It was only a joke after all, some stupid commentary that reflected on the attention the 900P had garnered at the show, but nevertheless, once that seed was planted, it had nothing left to do but grow.
And so sketches started appearing, quiet conversations shared, mutterings about new ideas and potential challenges filling the breaks between work. And from nothing, came something, a challenge: to make a watch as thin as the movement that got all this started, that calibre 9P from 1957.
Let me repeat that: an entire watch as thin as one of the thinnest calibres ever made. We’re talking 2mm, top to bottom, case, crystal, movement, dial, hands—everything. The 900P was a good start, but as the team would soon come to find, going from 3.65mm to 2mm was going to be much, much harder than they ever anticipated.
Once the concept was signed off, the team was assembled. This secret skunkworks project was built around a core of ten or so individuals, but with problem after problem arising from the very start to the very end, multiple specialists had to be enrolled throughout the development. This was proper prototyping, a new approach to watchmaking that would have to solve problems no one had ever encountered before.
The Piaget Altiplano Ultimate Concept is the world’s thinnest watch
The overall structure was to be fashioned in the same way as the 900P, utilising a monobloc case whose case back would also serve as the movement baseplate. But for the design to work, the case back could be no thicker than 0.12mm, and so the problems began. Gold was of course far too soft—but the big issue was that, at these dimensions, so was steel. Material engineers were recruited to source a replacement, settling on M64BC, a cobalt alloy with incredible hardness that’s forged with heat and pressure.
An ideal solution—except that none of Piaget’s tools worked with it. It was too hard. The equipment had to be updated, and even then, it frequently broke. And where the rubies had been set directly into the case back of the 900P, the paper-thin design of this new watch made that impossible, cracking jewels left, right and centre. Brass collars had to be handcrafted to fit each case back and each jewel, each and every one unique.
The team would soon discover a pattern here; in attempting to build a 2mm thick watch, it became clear that every single one would have to be custom-made to achieve the tolerances required, with no one component transferable from watch to watch. It was less a timepiece, and more an F1 engine.
This was only the beginning. For the next few years, this Altiplano Ultimate Concept would be what kept engineers lying awake at night, swung moods from soaring peaks to nauseating lows, that consumed every waking moment trying to overcome the challenges it left in its wake. And there was one thing that weighed on the mind of every single person working on the project: they could get 99% of the way to the finish line and hit a problem that rendered the whole thing scrap. That very nearly happened.
There wasn’t a single element of this watch that didn’t throw up something no one had anticipated. There was a plan, of course, but this was uncharted territory, unearthing situations that had never once occurred in watchmaking before.
To make a 2mm thick watch, there were a few key areas identified that would be the make-or-break for success, and one of them was the crown. To allow a crown to switch between winding and setting mode, a 90-degree gear is needed, and that would be too thick. A winding key was considered, as were two separate crowns, but those ideas felt like avoiding the problem rather than solving it.
Brains were wracked, nails chewed and coffee drunk until an idea was hatched: use an infinite screw—a worm gear—to transfer the direction of the mechanism instead! It was a great solution—except for the fact that it created even more problems. The crown couldn’t switch from winding to setting in the same way as normal, and so a telescopic crown tube had to be conceived, with a ratchet mechanism seated inside the crown itself to indicate the different crown positions.
But there was a much larger problem than that. In stress testing the watch, the infinite screw was wearing down too quickly—and I mean way too quickly. After just two weeks of daily winding, it was knackered. They tried resizing it, they tried various coatings, they tried thinking of other solutions—to no avail. There was only one thing left to try, and that was to develop a custom tool that allowed a watchmaker to hand polish it to a mirror finish, a process that took over five hours for the one screw. Thankfully, it worked. Unfortunately, that watchmaker has to do it again for every single watch.
Then there was the balance wheel. Getting it thin enough wasn’t too difficult—at least, relatively speaking—but what happened when it was seated below the crystal was a complete shock to everyone. As it beat back and forth, it began to speed up, losing its timing. The watchmakers discovered that it had become magnetised, but had no idea why. On its own, it ran fine, but in the watch, the same problem kept happening.
After a lot more coffee, nail-biting and late nights, a thought was occurred upon. The balance, being barely a hair’s width from the glass, might be generating a static field that was causing the hairspring to bind. The theory was absolutely right; it’s just no one had ever seen anything like before. An anti-static coating was applied to the underside of the crystal and the problem of weeks, was solved.
But the crystal itself was to prove to be the final stress that nearly destroyed the entire project. The watch was almost fully built, stress-tested, kinks ironed out—and in case you’re wondering if it’s likely to bend whilst wearing it, they tested that with a hammer to make sure it won’t. That’s not a joke. Even the strap is reinforced with Kevlar to make sure it’s thin enough and strong enough.
All that was left now was to secure the crystal in place permanently. You see, being a monobloc case, the hole where the crystal sits is the only entry point, and once the crystal is fixed in position, the watch is sealed. Adhesive was decided upon for the job, and with the sticky liquid applied, the 0.2mm thick crystal—the thinnest ever made—was lowered into place. Fitted fine, stayed stuck down—only problem was that the movement had stopped. After a lot of panicking, it turned out the adhesive had been compressed and spread into the movement itself, gluing it together.
So, they tried again, this time machining fine channels into the watch for the adhesive to pool in and keep it from spreading. With a sigh of relief, the watch continued to run. Now if it goes wrong and adhesive ruins a watch that took a month to build, the watchmaker has no one to blame but themself.
The end result is a watch 2mm thick, 22 grams including the strap, and an experience that has no equal. This is the very cutting edge of watchmaking, so far removed from what you or I are used to that it completely scrambles your brain trying to comprehend it.
The Product Manager who worked on the Altiplano Ultimate Concept and shared his experiences with me described holding the final product as almost underwhelming, the months and months of stress to solve problem after problem resulting in a watch that you can barely even feel.
And I completely understand. This is an alien thing, an object that I recognise in part yet have no frame of reference for in others, that takes watchmaking not to a new level, but an entirely new dimension. And you know what? I reckon they can make it even thinner.
Looking for a Piaget watch? Click here to shop now
