Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece

//Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece

Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece

The watch we’re going to look at has no case, dial, or hands; but it’s so beautiful on its own that casing it up would almost seem criminal. This is caliber 19 RMCCVEP. It’s an ultra-flat, minute repeater chronograph movement produced at a time when the initial partnership between Edmond Jaeger and Jacques-David LeCoultre was just starting to bear fruit. The partnership, which began around 1903, focused initially pretty intensively on the making of ultra-flat calibers, and led in short order to such engineering wonders as the caliber 145, which debuted in 1907 and was only 1.38 mm thick. A number of other makers were pushing the limits as well; Vacheron, for instance, experimented with a pocket watch movement that was .95 mm thick but that seems to have represented something of a practical limit in ultra-thin watchmaking with conventional technology, as they did not work reliably. Even today, a conventional watch movement thinner than 2 mm is very rare (the JLC caliber 849 is 1.85 mm thick, for comparison).

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061674

The movement is a bit thicker than the caliber 145, but not by much: only 42.86 mm in diameter, it manages to keep its thickness down to a mere 3.55 mm. This is a truly astonishing figure – the thinnest minute repeater wristwatch movement in current production today is from Bulgari, and that movement, BVL 362, is 3.12 mm thick. The JLC 19 RMCCVEP is less than half a millimeter thicker, and has a full column-wheel chronograph as well, and it was made around 1910, without the benefit of any of the modern milling, fabrication, and measuring devices that exist today. What JLC did have, of course, was a tremendous reserve of know-how in complicated watchmaking, as well as the benefit of some very sophisticated tools and precision measuring instruments that had been part of its heritage since 1844, when Antoine LeCoultre developed the millionometer – the first instrument capable of measuring the micron.

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP chronograph works  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061671

The image above shows the layout of the top plate of the movement. In watchmaking, what a layman would call the back of the movement – the side opposite the dial – is the top of the movement to a watchmaker. The balance wheel under its cock, with regulator sweep (“avance” and “retard” for faster/slower adjustment, respectively) is at the top of the image; it’s a standard, bimetallic compensating balance. Just to the lower right is the driving wheel for the chronograph, which sits atop the fourth wheel. The fourth wheel turns once a minute and most standard chronographs draw power from the fourth wheel.  

From the driving wheel, you can follow the flow of power from right to left; the wheel in the center is for the center chronograph seconds hand, and the wheel with 30 star-shaped teeth at about 8:00 indexes the 30 minute counter (a lot of the time in watchmaking you can figure out what a gear does by counting the number of teeth). The column wheel is at about 4:00, under a cap (a very traditional construction not used very often today; Patek Philippe still likes to put a steel cap over its column wheels). The repeater gongs, as well as the hammers, are also on the top plate (again, the traditional location for them, and where they are still found today in virtually all repeaters).

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP chrono center wheel  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061692

Above you can see the reset hammer for the chronograph center seconds hand. Even at this magnification, where generally speaking even the most well turned out movement starts to look a little the worse for the close-up, the quality of the steelwork is fantastic; movements of this quality, from this period, really give you a standard for evaluating movement finishing in modern movements (and I’m sorry to say that most will suffer by comparison).  

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP chrono column wheel  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061689

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP repeater hammers  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061695

In general the degree of preservation of the movement is excellent. There’s almost no corrosion at all on the steel elements. The baseplate is brass, with a gilt coating – in 1910 this would have been applied using the so-called fire gilding technique, in which gold is dissolved in mercury. That “amalgam” as it’s called, would then be applied to the brass plate, and the mercury driven off with heat (a potentially toxic process, by the way, which has been abandoned in favor of electroplating).

George Daniels has written, “After cleaning and scratch-brushing, the surface (of a gilt-finished watch movement) will be a lustrious, matt, lemon-yellow colour

[sic] which will resist stains and oxidation. The contrast of blue screws, polished steel, and gilded plates is most pleasing and refined and superior to any other finish.” Daniels was famously rather fond of ex cathedra pronouncements, but he was generally also right, and in this case I agree with him. Over the last 116 years, there has been some gradual oxidation of the underlying copper in the brass, but the condition of the movement overall is really impressive.

Now let’s take a look at the dial side, or bottom plate.

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP repeater works  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061668

The mechanism for a minute repeater is virtually always found on the top plate, or dial side of the movement. The reason for this is simple: the repeater works by mechanically sensing the position of the hands, based on the position of the motion works; motion works are called that, because they are the gears that put the hands in motion. Since the repeater mechanism has no eyes, it has to use touch: when you activate a repeater, three racks – levers, basically – are released and, under the pressure of blade springs, fall onto snails. The snails are stepped cams, and how far each rack falls is determined by how shallowly or deeply the rack falls, which in turn depends on how deep each step is. Just as with counting chronograph teeth, you can tell which snail is which by counting the number of steps.

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP hour and minute snails  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061680

Above, you can see some of the racks and snails in position. Right at the top center of the picture is the center of the movement, and there we have a gear that turns once an hour, and carries the minute hand. The odd-looking, vaguely starfish-like stepped cam on the same axis as that gear is the minute snail. The minute snail has four arms, and each arm has 14 steps. This seems a little weird until you remember that a minute repeater is organized around quarter hours (in fact, the earliest repeaters were quarter repeaters, which sounded only the hours and number of quarters past the hour). As the gear for the minute hand rotates, it carries the hour snail around with it, and when you activate the repeater, the tail of the minute rack falls onto one of the fourteen steps. As the minute rack then returns to its rest position – powered by a separate mainspring dedicated to running the repeater train – its teeth pass the trip of the hammer that strikes the minutes.

There are only 14 teeth because the maximum number of minutes that are ever struck is 14, when it’s 14 minutes past the last quarter-hour.  From 0 to 59 seconds past the quarter hour, no minutes should be struck. In order to keep 14 minutes from being struck when none should be struck, there’s a cam right under the minute snail, normally hidden, that jumps into position when the next quarter is reached; it’s there to block the tail of the minute rack from falling onto the bottom step of the snail, which would cause 14 minutes to be struck by mistake. This cam is called the surprise piece, and is one of the very few watch parts named for its action (“surprise!”) rather than for its function.

While it’s true that watchmaking is fundamentally a logical art, understanding how chiming watches work can be a bit of a heavy lift. There’s an essay from 1804 by a gentleman named François Crespe, of Geneva: Essai Sur Les Montres A Répétition, or Essay On Repeating Watches, which is written in the form of a dialogue between a master and a student. At one point (in a translation by Richard Watkins) Crespe’s student asks, rather plaintively, “Please give me a description of the surprise-piece, which few horologists can explain?” The basic principle, however, is pretty straightforward and once you understand the relationship between the snails and racks, you’re pretty much home free, at least as far as the fundamentals go.

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP minute rack and hammer trips  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061682

Above you can see the other end of the minute rack. If you count the teeth, you’ll find there are exactly 14 of them. Right next to the teeth you can see the trip for the minute hammer (remember, the hammers are on the other side of the movement).

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP repeater mainspring and setting mechanism  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061688

As with the chronograph side of the movement, it’s almost absurdly well done, and with all the quiet sense of style and pride of craft that make really high end Swiss watchmaking what it is. If you look at the cover plate for the hand-setting mechanism (roughly in the upper center of the image above) you can see that there is no real functional reason for it to have its rather whimsical shape – no reason except someone’s innate and sure eye for what works and what doesn’t.

Jaeger LeCoultre Ultra Thin Chronograph Repeater 19 RMCCVEP side view  Inside The Manufacture: With Jaeger-LeCoultre In Switzerland, Pt. 4: A 100-Year-Old Ultra Thin Mechanical Masterpiece P4061697

It’s when you get to see a movement like this that you understand just how incremental an art watchmaking really is. This movement is 116 years old, and yet there is an excellent chance that it’s the thinnest minute repeater chronograph anyone has ever made. It came, also, at a really pivotal moment in JLC’s history: the decade when LeCoultre and Jaeger formed their first partnership, which was one that transformed the company and made it not just one of the most important manufacturers in Switzerland, but also one of the preeminent watch design houses in the world, and turned it from a regional powerhouse into a globally aware cosmopolite.  

More than anything else, though, it’s a testimony to the hands that made it. The hands and brains that created the caliber 19 RMCCVEP are long gone, but they made something of real beauty, and if there’s some significance to watchmaking in general – and the best Swiss watchmaking in particular – it’s that its achievements are a tangible bridge across time to the people behind the watches.

See Parts 1-3 of our visit to Jaeger-LeCoultre, here, here, and here.

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By | 2016-12-23T20:17:27+00:00 April 20th, 2016|Blog|0 Comments

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