How do they make it: Grand Feu enamel dials from Donzé Cadrans
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(Wrist) Watch Presence: Horology’s first foray in elevating watch into timepiece

by Jonathan Ho on May 4, 2017

Wrist presence might appear to be a modern construct heralding from the first avant garde watches like Audemars Piguet’s Royal Oak but really what we recognise as “wrist presence” today, literally started out centuries ago as watch presence when watchmakers started lavishing decoration on pocket watches as a way of elevating watches beyond their utility and function and into a status symbol. From an economics standpoint, the 16th century watch was not only a feat of innovative engineering but also that of an exclusive precious object – they were expensive and while there was a practical needed for decoration (to retard corrosion for instance), it eventually became a means of signifying worth for object and owner. From there, horology as a feat of engineering and a study of astronomy and time was enjoined with artistry.

Watch Presence through Skeletonising: Horology’s first foray at elevating a watch into timepiece

A watchmaker’s primary task is engineering – the mainspring delivers enough torque to the gear train which in turn encourages the escapement and balance to consistent impulse and amplitude. Almost all decorative flourishes from engraved cases to enamel dials and faceted applied indexes exist apart from the movement; Skeletonising a watch enjoins art with physical sciences right at the heart of the timepiece, touching the mechanical components and the architecture holding it directly.

No one really knows when the practice started, 15th century watches didn’t possess mainplates or bridges (that would come later) but nevertheless, there was still a curiosity with the mechanical works, for the men who owned them and the men who made them – therein lies the raison d’etre for skeletonisation – exposing the mystery (at least for those unaccustomed to the physics behind the engineering).

Clocks are not watches but as far as the start of a phenomenon is concerned, openwork gothic table clocks from the 16th century gives us a pretty good idea at the growing decorative genre – iron frames with mechanical clockwork in full open view but that’s not enough, it’s one thing to simply just expose your innards, it’s another entirely to painstakingly cut into steel and brass to highlight and define the qualities of each component – watch with mainplates and bridges at its default and then lavishly cut into and finished. For that, the 17th century holds the genesis.

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As previously mentioned, the original calibres were bereft of plates and bridges as we know it today and they were unbearably thick and it took a Frenchman named Jean-Antoine Lepine to conceive what we recognise today in a modern movement. Apprenticed to André-Charles Caron at age 24 in 1744, Lepine eventually married his master’s daughter and operated under “Caron et Lepine”.

In 1760, the two French watchmakers Caron (the elder, not the daughter) and Lepine, began vying for the favour of the royal court – had presented watchmaking creations to intrigue the royal entourage – never before seen pocket watches with their movement plates intricately cut and exposing the myriad of turning gears and pinions, the barrel open, slowly and imperceptibly releasing stored potential energy and what was once a bridge, turning into the modern semblance of a triangular balance cock. More importantly, Lepine had conceived of the distinctive polished edges and embellished with decorative engraving (and not just on the structure but the components themselves)- but in keeping with decorum of the day, hidden away beneath an enamel dial, keeping the watch’s mystery only for her owner, visible through hunter case back.

 

By the time he became a maître horloger or master horologist in 1762, he was mentoring a business associate by the name of Abraham-Louis Breguet; all the while he was perfecting ideas for his revolutionary Lepine calibre. By the time he was appointed Horloger du Roi or Clockmaker to the King in 1766, his calibres were not only thinner as a result of the architecture he had conceived but his Lepine calibre à pont was eventually adopted by Breguet as well. Astute, Abraham Louis Breguet used the “calibre ponts” for his ultra slim watches but Parisian aesthetic sensibilities while a contrast to Breguet’s own functional and practical watchmaking philosophy, was about to blend his pioneering guillochage techniques to the craft of skeleton construction.

 

It must be said, skeletonising a watch does not make a watch more precise, in that respect, it would be an anathema to historical Breguet even if the artistry of design is very much his style and savoir faire of the modern namesake manufacture.  But first, let’s define what skeletonisation is not – they are not computer machined or cut and they certainly aren’t holes to be machine finished. No, genuine skeletonisation must be hand crafted in the order of the highest traditions of haute horlogerie.

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As mentioned in a previous article about Breguet’s functional decoration techniques, there are artistic and technical approaches to decoration. The choice of which components shoulded be skeletonised or open-worked hinges on whether it would be an aesthetic or functional choice. For instance, a component made lighter and thus more energy efficient would be a functional choice. If it is only made beautiful with no ensuing technical benefits, then it’s purely aesthetic. That said, this twin approach is purely a modern one, save Breguet and in the absence of computer-calculated simulations and models, decoration for the sake of decoration – the sort of filigree and arabesque often found on everything from swords to picture frames were trends of the era.

Today, modern computers can predict how decoration would affect a component for better or for worse and so, the technique has become a blend of two separate fields of endeavour. As a result of skeletonisation, a component can become lighter and thus more energy efficient but in doing so, a lighter mass renders it more susceptible to shocks and knocks thus – the watchmaker must weigh (no pun intended) his choices carefully – it would be like making a complication to compensate for the shortcomings of another unnecessary complication.

A simple rule of thumb, sharp interior angles or angles rentrants are the surest sign of hand finishing because those techniques are impossible for a machine to replicate (for now).

Lattice-work, the decoration process creates the diamond and square holes between plates, bridges and barrels are not just painstaking to cut but also, given the myriad of angles and planes, painstaking to finish. Using a process called “étirage”, watchmakers bevel the edges with a hand file and then polish it with wood to achieve a mirror finish called “anglage”. A simple rule of thumb, sharp interior angles or angles rentrants are the surest sign of hand finishing because those techniques are impossible for a machine to replicate (for now). A machine would simply file and round all the corners as it “removes material” during the polishing process – this alone separates the effort of a true artisan and that of the mass produced variety. It’s labour which demands countless hours of hand-finishing and naturally, one of the costs of high horology. Other techniques practiced at the highest names in watchmaking practice only hand finished étirage and anglage. At Breguet, other techniques like ciselage, the act of applying arabesque and other motifs is practiced and enhanced with the matt style brushed finishing or brossage.

A typical plate only has its edges and top and bottom sides to finish, whereas a skeletonised mainplate creates more complexity with interior and exterior edges, not to mention the various hand engraved motifs in the metal, thus, the time imposition and effort for the watchmaker are many-fold. For instance, lattice-worked bridges are significantly more fragile due to the lace-esque nature of what used to be a solid, singular piece of metal – apply to much pressure during polishing and it bends, any deformity would then potentially press against the swiftly moving parts of the gears – and for the field of micro-engineering, friction of this nature would be detrimental to the precision functioning of the timepiece.

A watchmaker inspects the skeletonised plate to ensure that it is completely straight and level

Likewise for the act of finishing a skeleton plate, a plaque rectifier is used to make sure that as a result of point pressure placed on the material during the decoration and engraving process the material didn’t deform or bend; given the minute tolerances between components, it would unduly affect optimal operation of the mechanism. Ironically, it is the bigger components which present a greater challenge for the watchmaker, a slight deformity on a small would be barely perceptible but a multitude of small ones add up to a big one on a bigger component – imagine a slightly off angle rifle shooting a target 2 metres away and again at 50 metres – the imprecision is multiplied the bigger the component.

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The mainspring barrel is particularly delicate because in its regular form, the solid cover is held to the drum by simple friction instead of a screw. If the skeletonised cover is even bent the slightest, it would not grip the edges of the drum correctly or worst of all, press down on the spring and harshly retarded the spring’s potential for energy release as it unwinds.

As an art, skeletonisation is almost as old as the industry itself. As a means of distinction, the practice and presence of such a tradition is as modern as the concept of wrist presence and it is one that while has changed in motive, it has not changed in artisanal terms and technique.

The skeleton bridges and plates are nicely finished, with the full package of chamfering and dressage.

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