Hardcore Engineering with De Bethune

Ask a man on the street, and he’ll describe the poster on his teenage bedroom wall, a red blur rocketing down the highway, or a centerfold in an unmentionable magazine. But prompt an historian of Sant’Agata’s finest, and the response will be “innovation;” the first mid-engined supercar; the fore-aft drivetrain of the Countach; the first roadgoing supercapacitors.

And so it is for De Bethune, a watchmaker known for Lamborghini-level visuals but defined by its engineering. Watchmaker Denis Flageollet is a third-generation practitioner of his craft. However, that legacy rides shotgun with a formal background in science. Some watchmakers are pure craftsmen; others are pure engineers; Flageollet is both. A full inventory of his inventions could fill a book. Consider this overview a highlight reel, not an encyclopedia.

The most obvious De Bethune innovation is its unique approach to ergonomics. Early versions of the company’s articulated lugs appeared on the DBS of 2005 and the DBD of 2006. At the time, a single upper hinge lug co-existed with a conventional lug at the base of the case. The concept of articulated lugs took a step forward with 2008’s Dream Watch; it combined the DBS’ upper hinge lug with two pivoted arms for the lower strap. Wrist fit improved, but Flageollet already was preparing the next generation, and it arrived with the DB26 perpetual calendar of 2008.

The “floating lug,” patented in 2006, allows the lugs and the case to be broken into separate structures: lugs to plant the watch on the wrist, and a case to contain the movement. Spring loaded and articulating, the floating lug reduces the impact of case size on wrist fit. In this manner, large cases and small wrists become a mutually inclusive pair. While not commonly discussed, several different sizes of floating lugs have been available over the years even on the same model, so collectors of De Bethune watches should keep an eye out for lugs — not just watches — that match their wrists. Factory lug retrofits of existing watches have been documented to tailor sizing for owners subsequent to the first.

Balance wheels represent the heart of any watch, and most independent watch brands purchase this component from suppliers. An ambitious small brand might create one proprietary balance. De Bethune has patented no fewer than ten unique balance wheels.

While the number seems excessive, the purpose is constant: create a better timekeeper. Early examples included titanium, platinum, and non-annular shapes including yokes and tri-spokes. Titanium, platinum, white gold, invar, brass, and silicon have been employed in service to three goals. First, reduce the impact of temperature change on timing precision. Second, maximize the percentage of total mass in the outermost rim of the wheel. Third, reduce the impact of aerodynamic drag on energy use. Flageollet is not sentimental, and models receive upgraded balances as soon as the new variant becomes available.

Related to balance design but advanced in sophistication, De Bethune’s tourbillon embodies the values of its creator. Patented in 2008, the ultra-light tourbillon is the world record holder for its type with a mass of eighteen hundredths of a gram — that’s 0.18g. This assembly nevertheless comprises 63 components made of gold, silicon, and titanium. Minimal tourbillon mass ensures De Bethune’s traditional long power reserve remains impressive at four to five days depending on the tourbillon model.

In addition to employing the latest De Bethune balance wheel technology, the tourbillon operates at a frequency of 36,000 vibrations per hour or ten beats per second. This helps to minimize the impacts of low-frequency wrist motions on the timing. Moreover, the tourbillon carriage rotates at a rate of two circuits per minute which Flageollet has determined is ideal for a tourbillon in a wristwatch application. The technology works. At the 2018 GPHG — the Oscars of watchmaking — De Bethune’s DB25 Starry Varius Chronomètre Tourbillon won the “Chronometry” category with a stated precision of ± 1 second per day or better from the company’s record-light mechanism.

Moonphase complications are as old as mechanical timekeeping, but De Bethune’s spherical design has broken new ground on this ancient turf. From its patent and market launch in 2004, the spherical moonphase display of De Bethune captures both the motion and the romance of lunar cycles. As a sphere, the De Bethune system reflects the true nature of the Earth’s natural satellite, and this is consistent with the way early moonphase displays were constructed in centuries past. Regardless of model, the programmed duration of the De Bethune moon matches the conventions of perpetual calendar moonphase displays at roughly 122 years between corrections.

More than a feat of engineering, this moonphase reflects an artisan’s touch. Each sphere is comprised of two hemispheres: one of steel, and one of precious metal palladium. When joined, the two halves form a uniformly silver sphere. Only when heated over a bed of brass shavings with flame from an oil lamp does the steel hemisphere oxidize to its ultimate deep blue luster.

While the steel of the moonphase is noteworthy, the aesthetic of De Bethune is defined by firing of another material: titanium. From the early 2000s through 2006, Flageollet experimented with heat-soaking and oxidizing grade five titanium. The temperature required for this process approaches 1,300°F and requires the component to be finished to a flawless degree prior to the application of heat. If guilloché, polish, media blasting, or engraving is to be applied to a component, it must be complete before the firing. The most celebrated application of this technique is to the long-running DB28 Kind of Blue, but many De Bethune watches incorporate at least a small amount of fired titanium.

Notably, there is more to the De Bethune oxidation technique than shades of blue. For example, the 2019 DB28 Yellow Tones exhibits a vivid yellow reminiscent of gold, but the entirety of the yellow metal is fired titanium. Zirconium also receives a unique oxidation when used on De Bethune watches; black oxide rather than simple PVD renders the metal more scratch resistant and striking to the eye. Moreover, there is a key difference between De Bethune’s oxidized colors and techniques like PVD used elsewhere in the industry to coat components. While PVD cannot be repaired if scratched, the De Bethune oxides can be restored by placing the components back in the firing kiln when the watch is returned to the factory for service.

Chronometry and durability combine through the De Bethune Triple Pare-Chute shock protection. Linear steel springs supported by the barrel bridge float atop a set of jewels while an Incabloc spring cushions the balance staff. While primitive versions of this system first arrived on the 2005 DBS, all variants from the earliest to the latest have three purposes. Firstly, survival of the watch hinges on protecting the delicate pivot points of the balance staff. If these fracture or flatten, a watch may stop altogether. Practical trials involving use by golf and tennis players in competition have validated the durability of Flageollet’s arrangement.

Beyond simple preservation, the flanking springs of Triple Pare-Chute have a chronometric purpose. Any time a balance staff pivot is displaced from its cup jewel, the timing of the watch is degraded. While a single shock protection spring might prevent damage to a watch, large gains or losses of time may result. De Bethune’s flanking linear springs can reduce the amount of shock transmitted through the balance bridge to the staff. As a result, the staff pivots are more likely to remain centered in their cup jewels during vigorous activity, and the chronometric qualities of the watch will be preserved better than with a staff-only shock system.

And the third purpose? Triple Pare-Chute looks cool. Early iterations employed a polished flat bridge with excellent mechanical qualities but aesthetic shortcomings. The definitive De Bethune balance bridge has emerged with a set of rounded arms whose diameters taper as they approach the flanking springs. Fully rounded and mirror-polished bridges are the preserve of the world’s most elite watchmakers. De Bethune’s workshop in L’Auberson proves itself equal to the most exacting bienfacture of Geneva, Neuchâtel, La Chaux-de-Fonds, and the Vallée de Joux.

As with Lamborghini, De Bethune knows how to make an entrance. Its watches are to the wrist what supercars are to the road. But look deeper, and L’Auberson’s finest make a case as fetish objects for philosophers, engineers, and artists. Ferruccio Lamborghini, who fancied himself all of the above, would have approved.