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Feature: How The World’s Thinnest Watch Was Made (Part 2)

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 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.

The Piaget Altiplano Ultimate weighs only 22 grams and is 2mm thick

The Piaget Altiplano Ultimate weighs only 22 grams and is 2mm thick

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.

The Piaget Altiplano Ultimate has the world’s thinnest watch crystal, only 0.2mm thick

The Piaget Altiplano Ultimate has the world’s thinnest watch crystal, only 0.2mm thick

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.

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