The horological elegance of skeleton watches
Not just time-telling devices, but miniature works of art, skeleton watches blend together mechanical complexity with architectural elegance.
History tells us that the first skeleton watch was created by André-Charles Caron in the 1760s. Born in 1698, Caron was a master clockmaker who worked at the court of King Louis XV of France. He was son of a watchmaker and later in life became father-in-law of another famous French clockmaker, Jean-Antoine Lepine, whose contribution to horology, which preceded Caron’s invention by a few years, was the simplification and considerable slimming of pocket watch movements. This contribution opened the way to further miniaturization and the development of the modern watch.
Perhaps as a result of the influence of humanistic trends such as Illuminism, Caron had the idea of rendering the inner mechanics of pocket watches visible, by removing the dial and skeletonizing the movement. This was the birth of skeleton watches, the ultimate form of minimalism and craftsmanship in watchmaking.
Skeletonized vs openworked watches
In skeleton watches, the watchmaker removes any non-essential metal from the movement leaving behind a skeleton of its components (e.g. bridges, mainplate, wheel train, etc.). Skeletonization requires several long hours of patient and painstaking chiseling and metal trimming, by the watchmaker. This process continues until the most essential parts of the movement are left, while ensuring that the resulting minimalism of the mechanics in the movement do not affect the structural integrity and reliability.
Luxury skeleton watches are meticulously hand decorated with various motifs using techniques and special tools that are centuries old in tradition, such as engraving, embellishing, and polishing. Purpose of skeletonization is to showcase exceptional craftsmanship and reveal the fascinating elements of a movement such as the balance wheel, the mainspring, and the escapement, and how they interact together.
Openworked dials are the window to skeletonized movements. The skeleton of the movement becomes visible through the face of the watch as the dial, or sections of it, is removed. Often, a transparent case back provides a view of the second face of the skeleton movement.
The revival of the skeleton watch
Following Caron’s time, skeleton watches lost popularity and became forgotten. They were revived in the early 19th century, when Samuel Frederic Ravené, watchmaker to the court of King Friedrich Wilhelm III of Prussia, created a quarter-repeating pocket watch, with a skeletonized engraved movement visible through the transparent center of a white enamel dial.
Fig. 1 — Samuel Frederic Ravené, Quarter-Repeating Pocket Watch
In the 1860s, Patek Philippe produced a small series of skeleton pocket watches for exhibition purposes, to showcase the brand’s horological savoir faire. These pocket watches were eventually commercialized starting in the late 1970s.
There aren’t many skeleton watches that pre-date the quartz crisis, which began in 1969 with the launch by Seiko of the Astron 35SQ. The quartz revolution drove several Swiss brands to reposition themselves to the higher end of the market shifting their focus from precision to technical creativity and luxury. Since then, brands like Vacheron Constantin, Audemars Piguet, Patek Philippe, and Jaeger LeCoultre have become renowned for their ability to create skeletonized movements with intricate decorative motifs and elegant architectures.
Two approaches to creating a skeleton watch
The hand skeletonization of a movement is a rare craft and the result of a long and laborious process, from a highly skilled and experienced watchmaker. The artisan-watchmaker starts from an existing movement and chisels material away to achieve the desired new architecture. The objective is to enhance the transparency and the aesthetic appeal of the inner workings of the watch, without jeopardizing its functionality and reliability.
Refinements such as decorations and finishing are often meticulously applied to the skeletonized movement. These will include intricate motif engravings, guilloché patterns (precise intricate and repetitive engraved patterns), Cotes de Geneve (straight line engravings), perlage (patterns of small overlapping circles), Rhodium plating, beveling and polishing.
The engravings alone of the skeletonized Patek Philippe Calatrava in Fig. 2 have required about 130 hours of artisanal work, as described by the brand on its website. The absence of a dial and the presence of a sapphire crystal case back in the Calatrava Skeleton make it an exciting through-and-through visual experience.
The watch’s movement is only 2.53mm thick. It is a statement of the delicate balancing act that skeletalization plays between aesthetic appeal and mechanical integrity. Anything more removed from the movement would make it too fragile and its chronometry would be compromised.
Fig. 2 — The Patek Philippe Calatrava Skeleton
During the last 20 years, advances in computer-aided design and manufacturing (CAD-CAM) have made the production of skeletonized movements more accessible to more brands. Using modern technology, watchmakers can pre-engineer a skeleton movement, to deliver maximum visual impact with designs that are impossible to replicate by hand.
Calculations can be made to evaluate the torsional limits of the materials used in the movement and the exact amount required, which reduces waste. Modern lighter and stronger materials such as titanium and forged carbon introduced from the aerospace and F1 racing industries have further enhanced the structural resistance of skeleton movements.
You like or hate it
Not all watch enthusiasts agree with the idea of skeletonization: legibility and fragility are often the undesired outcomes of skeletonization. Openworked watches with fully skeletonized movement do not facilitate the reading of time, as the hour and minute hands are lost in the intricate architecture of the movement. When the number of components increases because of the presence of a complication, the architecture of the movement becomes complex, without a discernible design or logic, and may lack the three-dimensional perspective that is usually expected in skeleton watches.
In recent years, the use of coloration has helped simplify the reading of time. Coloring techniques like Physical Vapour Deposition (PVD) are frequently used in high-end watches to color bridge’s, main plates, and the wheel train. In the Piaget Polo Skeleton (see Fig. 3), a blue PVD coating is applied to parts of the movement to create a useful degree of contrast and a three-dimensional perspective that enhances legibility.
Fig. 3 — The Piaget Polo Skeleton
In modern days, there has been a growing interest from consumers for skeleton watches and several brands from the mid to high end of the market are offering skeleton watches in their product lines. For these consumers, a skeleton watch is not designed to tell time but rather to show off craftsmanship and represent a work of art. It is meant to deliver a unique experience as there are no two skeleton watches that are exactly alike. For these watch collectors and enthusiasts, the gazing at the inner workings of the movement, at the rhythm with which they interact with each other, at their craftsmanship and decorations, will deliver a powerful emotion.
Great read! Love the topic of skeletonized watches and how much chaos it causes in the watch community; to me, if well done, a skeletonized dial is a piece of art, but if done cheaply, it’s in the bin 😂