Tough Tech: Shock Resistance

“Tough Tech” is Worn & Wound’s series that takes a deep dive into the technologies that protect our watches, covering their use throughout watchmaking history, functional benefits, and the watches they’re used in. Check out the first installment on antimagnetic watches right here.

One of the reasons watches are so interesting to me on a personal level is the astonishment I sometimes feel when I consider the fact that these little mechanical tools even work at all. Think about: in a case of stainless steel, or some other metal, you have a finely tuned network of springs and gears that not only work in tandem with each other, but can keep track of the time, a more elusive resource I cannot think of, to mere seconds per day. And it’s all done while you wear it on your body. Consider for a moment the things that your body goes through during the day. It’s in constant motion, subject to sudden changes in direction, and must regularly adapt to forces far beyond its control. And yet your watch ticks on without complaint.

In this installment of our ongoing Tough Tech series, we’ll take a look at the reason your watch can withstand the bumps and jostles of everyday life. Shock resistance has been built into watches for decades – it’s one of the primary reasons wristwatches were ever able to take off in the first place. The ways that watch movements have been protected over the years has changed dramatically in many respects, but the fundamental principles behind shock resistance remain.

Watches are inherently delicate. The balance wheel in particular, which is constantly in motion at a fairly high rate of speed compared to the other moving components of a watch movement, is at an ever present risk of being knocked off plane by the slightest interruption. Timekeeping and the watch’s ability to function at all can be enormously impacted.

The most primitive and the earliest widespread method of protecting the balance from shock is the Incabloc system. If you’ve even dabbled a little bit in vintage watches, you’ve almost certainly seen the Incabloc signature on many a watch dial. 

Incabloc was developed and eventually trademarked by the Portescap company in 1933. Portescap is a Swiss company that still exists today, specializing in the production of miniature motorized devices, although they are no longer involved with Incabloc, which has long since been spun off as a separate entity.

The idea behind Incabloc is relatively simple. It works by allowing a watch’s balance staff (the component to which the balance wheel is mounted to) to move in small amounts both laterally and vertically, which keeps this delicate part from snapping due to a sudden impact. If this seems counter intuitive, think of the suspension in a car. A very stiff suspension means a bumpy, less forgiving ride (but lots of control, which is why a stiffer suspension is favored in performance vehicles made for getting around a track very quickly). A suspension that allows a vehicle’s chassis to absorb impacts as they come is generally going to be more comfortable, and not result in bags of groceries flying everywhere if, for example, you miss a speedbump (not that I’m speaking from personal experience).

Incabloc systems have made the once common problem of a broken balance staff a rarity. But there are other ways a watch movement can be damaged, and there’s been a great deal of innovation in protecting watches from abuse as they’ve become more and more associated with the performance of demanding physical activities. Now that such a large percentage of all watches sold could be classified as some form of sports watch (many designed to be used under harsh conditions) there’s a need to think about shock protection in ways that we didn’t through the midpoint of the 20th century. 

Earlier this year, we covered one of the toughest, most shock resistant watches we’ve come across, the SēL Instrument OmniDiver. The OmniDiver incorporates a slew of technical innovations that keep it safe from drops, shocks, and vibrations (whether or not you select the quartz or mechanical version), but one that really stands out as a differentiating factor is the shock isolated crystal. The Omnidiver’s crystal is made from Kyropoulis sapphire glass and 6mm thick, making it strong and naturally fracture resistant, but still vulnerable to direct, focused impacts, a primary concern for SeL founder Andrew McLean. As part of his philosophy of overbuilding everything, McLean seeks to make his watches virtually indestructible, even if many owners will never actually be at risk of damaging his monster crystal. 

The solution he’s come up with is fairly ingenious, and borrows a bit from the old Incabloc method. Instead of mounting the crystal to the case in a rigid way, which is the traditional way of fusing these components together, the OmniDiver’s crystal is attached using a shock isolated suspension mount. This allows the crystal to travel a bit in the event of an impact, greatly reducing the chances of it failing. This design has the added benefit of reducing shockwave transmission throughout the entire case, making the whole watch more resistant to harmful impacts. 

While early anti-shock systems for watches focused on the balance wheel and balance staff, the increased prevalence of automatic watches over the last several decades has introduced challenges with their swinging rotors and additional moving pieces and points of wear and possible breakage. Ball, a brand with deep American heritage rooted in chronometric precision, has their own anti-shock system known as the Amortiser, which, in certain variants, includes the capability to lock the rotor in place on command, reducing the likelihood of it being damaged (or becoming a source of damage) during an impact. 

Unlike the shock absorption systems previously discussed, which work by allowing sensitive pieces of the watch to travel in controlled ways once impacted, the Amortiser can be thought of as a type of armor that protects the entire movement. On Ball watches with the Amortiser technology, the caliber is surrounded by a rigid metal ring that is designed to fully absorb an impact before it reaches the sensitive movement components. Ball also incorporates another system that they call SpringLOCK, which acts as a cage protecting the balance spring assembly. It’s a type of further insurance against shock, should an impact breach the Amortiser. 

On some Ball watches, the Amortiser and SpringLOCK systems are combined with a rotor locking function, which allows the user to essentially flip a switch on the case, which keeps the rotor from spinning. The thinking here is that a freely spinning rotor that is mechanically connected to the rest of the movement poses an inherent risk of transmitting shocks and vibrations to the smaller, lighter, and more sensitive parts of the movement. Locking the rotor in place reduces the possibility that the rotor itself would be a vector for damage should the watch experience a shock. 

Materials can also play a significant role in reducing the effects of shocks and vibrations. This should be fairly obvious – we can all gather somewhat intuitively that certain materials possess qualities of rigidity or density that would make them well suited to protecting something delicate. Damasko, in their DC 56 Si, use materials throughout the movement that contribute to the watch’s overall stability against impacts. This particular watch is even DIN certified as shockproof. 

Similar to Ball, the Damasko’s focus is primarily on the rotor. Rather than stopping it, however, Damasko has elected to manufacture it in such a way that it becomes inherently less likely to suffer shock. This pilot’s chronograph is powered by a Valjoux 7750, but Damasko has replaced the standard off the shelf rotor assembly with an in-house bearing system using ceramic components that are more vibration resistant than the supplied materials. The vibration resistant ceramic is also incredibly durable and resistant to wear and tear, which should reduce service intervals. Damasko also uses a silicon balance spring which they call the EPS-Spring, that has been developed to be highly elastic, and thus moderately more resistant to shock.

To this point, the watches we’ve discussed have been relatively affordable, in spite of the sometimes novel engineering at play. But there’s another end to the anti-shock spectrum. Richard Mille is a luxury watch brand that’s known, in part, for the stratospheric retail price of their watches. We’re talking hundreds of thousands of dollars for certain examples – these are objects that are meant to convey status. That, however, does not mean that there isn’t real innovation present. While industry observers and watch buyers will have good natured arguments over whether a Richard Mille watch is worth the asking price, the tech, in many cases, speaks for itself. 

Let’s look at perhaps the most visible and widely seen Richard Mille, at least at the moment, the RM 27-03. Even if you’re not a watch fan (and if that’s the case, good on you for somehow finding this corner of the internet), if you’ve watched a professional tennis tournament, or even just the highlights, you’ve probably seen the RM 27-03 strapped to the wrist of Rafael Nadal, one of the top tennis stars of his generation. This particular version is hard to miss when Nadal wears it while playing, being made from a Quartz TPT compound in the colors of the Spanish flag. It’s a loud design with a ton of wrist presence, which is probably what you want if you’re ponying up over $700,000 for one of these. 

The RM 27-03 (and the other watches Richard Mille has made with Nadal in mind) are designed with the idea that they can be safely worn during a tennis match. Now, that’s not to say that a normal, modern sports watch with industry standard anti-shock capabilities can’t handle some tennis. I’d wager that most could. But this watch, in typical Richard Mille fashion, has been engineered in a completely over the top way.

According to the brand, the movement can withstand shocks up to 10,000 Gs, which is a shockingly high number. In developing the watch, Richard Mille performed shock tests by using a swinging, weighted pendulum that would impact the watch at increasingly high G levels. This is basically like taking a baseball bat, or a golf club, or, indeed, a tennis racket to the watch at an impact level it’s not likely to experience in a real world situation. 

Once again, materials are key to achieving strong resistance, but in a different way than the Damasko above. The bridges (visible through the open dial) are made of titanium, and the baseplate is Carbon TPT. Carbon TPT is a high tech material that’s made from separated threads of carbon fiber. These threads run in parallel to each other, are combined with resin and then heated. The end result is a material that’s incredibly strong and sturdy. It’s worth pointing out that the RM 27-03 has a unibody design where the midcase has been eliminated – the baseplate is an integral part of the case construction itself, and the whole package is extremely lightweight, an essential feature if it’s to be worn by a top athlete. Also, it’s a tourbillon. No big deal. 

Whether you’re a professional tennis player, or just an average guy who tends to bang his watch on a door jam from time to time, anti-shock systems in watches, even basic ones, are critical to keeping them functional. They’re also an opportunity for brands to flex their engineering muscle. Ball’s Amortiser and rotor locking system, for example, might have limited utility for most, but there’s a pleasure to be had in knowing that you have something so finely tuned and well thought out on your wrist. And that’s really the nature of continued advancements in watchmaking in a nutshell: even though it might be unnecessary, this type of tech continues to push the hobby forward, keep us talking, and wondering about the next great parlor trick.