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Feature: How Do You Know When A Watch Is Finished?

If you’ve been around watches long enough, you’ll be familiar with the term “finishing”. That’s where you’ve made the thing, but you just want to give it a last little touch up to make it look nice, and in the case of watchmaking, it’s one of the hardest parts to master. And if you’re going to master it, may as well do it properly, as Jochen Benzinger of Benzinger watches has demonstrated not once, but twice with the Subscription IV Silver Blue.

Engine Turning

You may already be familiar with the term “engine turning”, because it’s not one limited to watchmaking. The inscriptions of fine geometric patterns onto a metal surface, engine turning can be found anywhere from classic car dashboards to the outer skin of Charles Lindbergh’s record-breaking plane, the Spirit of St. Louis. The repeating circular pattern turns a dull piece of metal into something jewel-like. It’s a labour-intensive process, each gleaming circle applied one after the other with a drill press.

It’s not, however, anything like as intensive as the engine turning we’re talking about here. This is the original engine turning, a four-hundred-year-old process said to be attributed to a Frenchman known only as Guillot. You may have already guessed that I am indeed talking about guilloché.

First with wood, then soft, precious metals and glass, guilloché has long been known for its incredibly tight, incredibly perfect concentric patterns. It was first seen on a watch in 1680, with Jean-Antoine Lépine spearheading its popularity. Side note: Abraham-Louis Breguet was another heavy user of guilloché, a preference he was believed to have inherited from the apprenticeship he was understood to have had with Lépine. Another side note: it was also Lépine who first designed what have now become known as “Breguet hands”. Doesn’t seem fair.

The application of guilloché is as much mathematical as it is artistic, the rose engine—the specific type of lathe used to engrave circular guilloché—unconstrained in its possibilities, unlocked only by experience and understanding. Every pattern can be defined as an equation, and as such every pattern has a large scale template, shrunk down through the gearing of the rose engine to its final size. There may be some patterns that have just one purpose and are seldom used but no less important. Such is the intricacy and difficultly of the application of guilloché that it was used on the printing plates of bank notes for hundreds of years to prevent forgery. The concept is still found today—albeit digitally—in the production of modern currency.

The principle is not unlike that of the classic toy Spirograph, with the rose engines used by Jochen Benzinger to decorate the dials of his watches—some of which are over a century old—driven by hand. These monolithic machines, of which Benzinger has ten, are as finickity as they are heavy—and they are unimaginably heavy. Apply too much or too little pressure, too much or too little speed, and like the Spirograph, the result is imperfect. Make just one mistake, like the Spirograph, and the whole work is ruined. When a complete dial can take hours and even days, a single slip can be a costly mistake.

With increased precision in manufacture in the 1930s, guilloché found its way onto more mass-market, consumer-friendly items, but with the arrival of the wristwatch and their paper-thin dials, the challenge of sharp, precise engine-turning on watches was as great as ever. Unfortunately, with the decline of guilloché in the decoration of modern luxury goods, the art is slowly being lost today. With passable impressions achievable with CNC machining, guilloché has become a skill handed down by one practitioner to another, a finish once found on the finest luxuries like Fabergé eggs—now rarely seen in its traditional application like it is here on this Subscription IV.


If you thought that sounded like effort, this next level of finishing is quite simply god-tier. In the 17th century, when mechanical clocks were getting a bit old hat, clockmaker André Charles Caron had an idea. He surmised that the populous wasn’t bored with clockmaking per se, just the way it was presented to them. They did not get to see the mechanical wizardry going on inside, and so he decided to show them.

And so, with painstaking care, Caron cut away at the dials and movements of his clocks, leaving behind a structural arrangement enough to maintain practical operation whilst also revealing the work he was most proud of: the mechanism inside. The style was a hit not just with his peers, but also within the royal courts of France, his work earning the attention of King Louis XV.

Caron ascended to his place as master clockmaker to the king, where his work on skeletonisation—as it would come to be termed—became legend. His skills were greatly desired amongst young watchmakers looking to themselves achieve greatness, and so Caron inherited not just an apprentice, but also a son-in-law, in one Jean-Antoine Lépine. Name sound familiar? He’s the guy that popularised guilloché from the last segment. He also reinvented the way pocket watch movements were arranged such that skeletonization was possible in portable form, too, a structural code the modern calibre still adheres to.

There’s a distinct reason that follows a common theme here that prevented skeletonisation becoming more common: it is very, very hard. Yes, like with guilloché, modern CNC can do a pretty good impersonation, but done now as it was then, with a fine saw blade powered by nothing but elbow grease, yields the finest result. It’s in the details—to be more specific, the acute corners. A CNC mill is limited by the bore of its cutting bits, a constraint betrayed by rounded corners, whereas a saw driven by hand can cut to an infinite point. The downside is that for the days taken to complete a hand skeletonised movement, a machine can produce many multiples.

One of the myriad upsides, however, is that your watch can be hand skeletonised in a pattern that is unique to you, with the only limitations being the key structural points of the movement—screws, jewels etcetera—and the imagination. It can also be embellished with hand engraving for, say, a traditional floral motif—or why not really show off, as Jochen Benzinger has done here, by being the only watchmaker to successfully combine skeletonisation and guilloché together?

But the work is not done yet. Where CNC machining leaves a finish that many may deem acceptable, hand skeletonisation comes with all the irregularities associated with human imperfection, which must then be hand-filed out nanometre by nanometre to achieve a uniform surface. As with guilloché, the net result is that hand skeletonisation is going the way of the Dodo, an artistry understood by few and appreciated by even fewer.

The cumulative labour demanded by all this finishing work means that Jochen Benzinger can only make around 100 watches per year—to do more would undermine the traditions of hand guilloché, engraving and skeletonisation that he so admires and seeks to preserve. It may sit at odds with the modern ethos of high-end watchmaking to dress a basic movement up in such finery, but the reality is that there’s more tradition in one room at Benzinger’s workshop than there is in the entire factories of some so-called classic watchmakers. “But,” you might say, “isn’t there that brand Chronoswiss that did that high-end skeletonised piece too?” Yes, you’re right, there is—and they got Jochen Benzinger to do it.