Patek Philippe has, for better or worse, become synonymous in the minds of many enthusiasts with the Nautilus – a stainless steel sports watch that launched in 1976 and which has been having a very prolonged moment in the spotlight. However, as Thierry Stern told HODINKEE’s Nick Marino at Watches & Wonders 2022, the company is not satisfied to be thought of as just a maker of on-trend steel bracelet watches, and its releases for the show were a reminder that Patek isn’t Patek because one watch became an Instagram darling.
The two pillars of watchmaking at Patek have always been quality in finishing and irreproachable execution in the making of complicated watches, and its history is full of examples of watches that combine both, including the Henry Graves Supercomplication and, in more recent years, the Grandmaster Chime (polarizing in its aesthetics, but imposingly innovative in its mechanism).
Today, Patek Philippe Monopusher Chronograph 5470 has just announced a new chronograph that’s both extremely sophisticated technically, and also further hammers home the point that a Patek complication is meant to be a benchmark for horology, in general. The Patek Ref. 5470P-001 1/10th Second Monopusher Chronograph isn’t the first high-beat chronograph, of course – 1/10th of a second chronographs have been around ever since the launch of the Zenith El Primero, in 1969. But if it’s been a long wait for Patek to release a high-beat chronograph, it’s been worth the wait – the Ref. 54070P-001 1/10th is unlike any other high-beat chronograph.
At first glance, this looks like an absolutely classic platinum two-register chronograph (with a small diamond in between the lugs at six o’clock, like all platinum Patek watches). The red center hand, which at first glance is the chronograph seconds hand, looks a little unusual, especially against the deep blue dial, but otherwise, this could just as easily be a Patek chronograph from 1952 as from 2022. On closer inspection, however, you notice that there are actually two chronograph center hands, and that the dial reads “1/10 second” in small, diffident letters – and then that the outer elapsed seconds scale is actually two scales, one graduated for elapsed seconds (and minutes, when read off from the minute hand) and an outer one, with 12 red indexes, meant to allow you to read off 1/10 of a second increments from the red center chronograph hand. The red chrono hand rotates once around the dial once every 12 seconds.
The 1/10 second action is courtesy of a new movement. This is the caliber CH 29-535 PS 1/10, which took as its point of departure the rattrapante chronograph caliber CH 29-535, which debuted in 2009, and you can see the rattrapante lineage in the new movement, in the superimposition of the 1/10 second chronograph hand and the chronograph second hand, when the chrono is reset to zero. The entire mechanism was rebuilt to accommodate the 1/10 second system, beginning with the escapement and oscillator.
The oscillating system is Patek’s patented Oscillomax system, which was first introduced in an Advanced Research Project watch from 2011 – the Patek Philippe Advanced Research Ref. 5550P. The Oscillomax system incorporates a silicon balance spring, a silicon escape wheel with a special tooth profile, and most visibly, the unusual GyromaxSi balance. The GyromaxSi balance is obviously and dramatically different from other, annular balances made of Glucydur – it’s made of silicon (hence the “Si”) and has gold inertia weights, with a butterfly-shaped profile that instantly flags the caliber CH 29-535 PS 1/10 as a very different animal from its rattrapante predecessor. Despite its very unusual configuration, it still has the adjustable weights for timing found in Patek’s Gyromax balance – a very visible connection between tradition and cutting-edge materials-science-based watchmaking. Silicon is often the solution to some of the problems posed by fast-beat escapements – the cal. CH 29-535 PS rattrapante has a frequency of 28,800 vph, but bumped up to 36,000 vph (from 4Hz to 5Hz) you have problems with inertia you don’t have at a lower frequency, which is where the reduced mass of silicon comes in (and you get the added advantage of using a paramagnetic material, as well). In the caliber CH 29-535 PS 1/10, the system for the 1/10 second train is driven off the fourth wheel of the movement. The driving wheel is in two parts – an upper wheel with flexible spokes, and a lower one with rigid spokes. The lower wheel is driven from the fourth wheel and the upper one drives the clutch wheel – a system that helps prevent backlash between the driving wheel and clutch. The 12-second rotation of the 1/10 second chronograph hand is thanks to a pinion on the 1/10 second wheel with micro-toothing, and I do mean micro – there are 136 teeth on a pinion just 1.46mm in diameter, with a tooth height of 30 microns.
There are essentially two separate chronograph mechanisms – one for the tenth-of-a-second mechanism, and the other for the standard, center seconds counter and instantaneous jumping minute counter. The entire 1/10 second mechanism is carried on the clutch lever and both the base system and 1/10 system are traditional, lateral clutch chronographs. The 1/10 second system consists of the anti-backlash wheel (driven by the fourth wheel) with its rigid lower and flexible upper wheels. The upper anti-backlash wheel serves to stabilize the driving wheel (below, in yellow) when the chronograph is engaged, to prevent the 1/10 second pinion (and therefore, the hand) from stuttering. The reason Patek didn’t use anti-backlash split teeth on the 1/10 second pinion (flexible gear teeth split down the center, which act like tiny springs) is because the teeth on the pinion are too small. Since the 1/10 second clutch lever carries the entire 1/10 second system, it’s much heavier than a conventional lateral clutch chrono lever. That, plus the fact that the 1/10 pinion’s teeth are so tiny, means that if there’s a shock, the 1/10 second clutch wheel might come out of engagement with the 1/10 second pinion. Patek’s patented a new anti-shock system, with two “pendulum” anti-shock levers. These are configured in such a way that no matter what direction a shock comes from – top or bottom, left or right – the clutch wheel is actually pressed more firmly against the 1/10 second pinion. An analogy might be the caseback of a water-resistant watch (or a submarine hatch, for that matter) which is designed so that the more water pressure increases, the tighter the seal.
Because the 1/10 second mechanism exactly follows the movement of the lower clutch system for the standard chronograph system, you need some protection there, too. Patek’s achieved this by adding a shock-absorbing hook spring which, when the chrono is running, hooks into a matching hook under the round plate on top of the column wheel. When the chronograph is switched off, the hook is lifted off the the safety hook under the column wheel top plate and the lever is free to move.
For this sort of movement, you take every inch of ground you can in terms of technical improvements, and another tweak made by Patek is to the mainspring barrel. The length of the mainspring and the number of coils (two of the basic factors determining power reserve) were both increased by decreasing the diameter of the central arbor that carries the innermost mainspring coil. That particular point was, in the past, a common source of breakage and to hedge against any risk of excessive tension, Patek Philippe Monopusher Chronograph 5470 also modified the slipping bridle on the outer coil of the mainspring, as well as strengthening the point of attachment of the mainspring (made of Nivaflex) on the arbor.
One final element in terms of power management is the 1/10 second hand. Patek decided against using tempered steel and instead, opted for a hand made of Silinvar (silicon with a silicon oxide coating). The Silinvar hand has exactly 3.35 times lower inertia than a steel hand, which means less energy required to both run the hand, and reset it to the zero position. This, however, presented two additional problems. The first is that silicon is too brittle for the hand to be pressed onto its friction-fit post and the second is that ordinary red paint wouldn’t adhere to the hand. Patek solved these problems by patenting a primer formulation that would let them color the hand red, and by patenting a second process for attaching a hollow brass pipe to the center of the hand, allowing it to be set. The upshot of all of this is that you have a 1/10 second movement, with a central chronograph seconds hand and a 1/10 second hand, with an extremely sophisticated oscillating system and a highly optimized driving system. The new CH 29-535 PS 1/10 is actually slightly thinner than the rattrapante version, by 0.15mm – the rattrapante version is 7.1mm thick, and the CH 29-535 PS 1/10 is 6.96mm thick. The movement development, by the way, took place under the supervision of Patek’s head of research and development, Philip Baralt, and Anthony Krüttly, head of watch research, and as far as I’m concerned the entire community of watch enthusiasts ought to send them a magnum of champagne and a dozen roses, because I can’t remember the last time I saw a caliber with so many unbelievably unconventional and imaginative technical solutions.
If you compare the caliber CH 29-535 PS 1/10 to the El Primero caliber 3600, the biggest difference you’ll notice is in the driving and coupling systems. The caliber 3600, used in the Zenith Chronomaster Sport, has a center 1/10 seconds hand that rotates slightly faster than the CH 29-535 PS 1/10, at one rotation every ten seconds. The system in the caliber 3600, however, is driven off the escape wheel, rather than the fourth wheel. Generally speaking, you don’t want to drive anything off the escape wheel because the torque there is pretty low already, but Zenith has figured out a way to make it work. The Patek Philippe Monopusher Chronograph 5470 system uses a wheel one gear back in the train, so the energy available is higher, and Patek’s system, which is optimized in a number of unique ways (and I do mean unique, there are 31 patents associated with the movement of which seven are completely new) represents a completely new approach to constructing a high-frequency chronograph – while retaining one feature common to virtually all classic lateral clutch chronographs, which is driving the chrono train from the fourth wheel. You would expect this to be a limited edition, but it’s going into the regular collection, albeit I wouldn’t expect the number of units produced per year to be very high – and the price is “on request” which generally does not speak to a high volume output, to put it mildly. It’s a beautifully traditional design with some of the most sophisticated and refined watchmaking I’ve ever seen in a high-beat chronograph – further proof that if you want actual horological content for your hard-earned pennies, it’s still very hard to beat Patek Philippe.