The Twilight of the Full-Bridge

July 11, 2000

The dark age of mechanical watches fades into dim memory as a new golden age of Swiss and German mechanical watchmaking is created by rapidly expanding watch consumption around the world. Yet the dark age of hand-wound movements continues, with the greatest fruit of the hand-wound tradition — the full-bridge movement — falling into a deepening twilight.

The several hundred year history of mechanical watches is very much a tradition of hand-winding by key or crown, a tradition recently usurped in the early to mid 20th century by the “automatic” watch. It is the automatic with its symbiotic, quartz-like autonomy which leads this new golden age of expansion and consumption.

Few options remain to the purist who seeks the classical form and feel. Short of spending a few thousand dollars, the offerings are largely limited to the robust but ugly 2801 of ETA, the functional but inelegant Peseux calibres also owned by ETA, and Minerva’s limited production calibre 48 (and 49). Minerva is unique in offering a modern manufactured vintage design, and is the only full-bridge calibre at this price point. Its authenticity has given it a cult status even amongst those otherwise uninterested in hand-wound movements.

Classical handwinds have a small haven at more rarefied price levels — the much less accessible “top tier” of fine watchmaking. Yet even here, classical full-bridge designs have begun to slip away, either through compromise or by intent. The twilight represents not the complete extinction full-bridge design, but rather its decline or decadence.

It is perhaps strange to realize that we often define movements by their top-plate architecture, but it is the top-plate that gives us our first and often only impression of a movement. Unlike the more esoteric hidden beauty of beveled pinion teeth, and the other mysteries of mainplate finishing — the beauty of soul so to speak — the top plate is very much the “face” of the movement, particulary in this age of display-back fetishism. Oftentimes our entire opinion of a movement is formed upon the design and finish of the top plate components.

While I do not intend to overstate the importance of top-plate design, I think that the beauty of any artifact can or must be gauged against its ideal form. The movement of a watch is as much a concept as it is a machine, and it is the form of the machine that delights us with its beauty as much as the function of the machine delights us with its precision.

There are few top-plate designs which have been used for wristwatch calibres. The first we’ll discuss is the 3/4 plate made famous by the recreation of Glashutte manufacture
A. Lange and Sohne. Some of the earliest wristwatches used small 3/4 plate movements originally intended for use in ladies pocket watches. 3/4 plates are also commonly used as a basis for traditional handwound chronographs, as can be seen from the calibres 1874, 2220, and 2320 of

The design of the 3/4 plate calibre is a result of the simplification of the earlier full-plate design. By bringing the balance bridge down to the same plane as the gear train, the 3/4 plate resulted a movement that was thinner, mechanically simpler, and more efficient. With a bridge for the balance wheel, (sometimes) a bridge for the escape wheel, and the sum of the gear train and mainspring barrel beneath a large 3/4 plate, it remains the simplest form of hand-wound

Many full-bridge calibres employ a design utilizing four bridges, of which Philippe Dufour’s calibre 11 (shown above) is the crowing glory. In this case, the four bridges consist of three cocks to hold the balance, escape, and fourth wheels, with the sum of the gear train, mainspring barrel, and crown wheel held by one large bridge. In his article on
movement plates, Peter Chong refers to this as a “half-plate” design.

This Lange wristwatch movement from 1937 shows another form of the four-bridge calibre, employing two cocks for the balance and escape wheels, a large main bridge which holds the center, third, and fourth wheels, and a bridge for the mainspring barrel and crown wheel. This design is common to Jaeger-LeCoultre’s handwinds including the present production calibres 803, 818, 822, and
849, and a vintage Vacheron recently
analyzed by Walt Odets shows that this form is also an important part of Jaeger-LeCoultre’s calibre design tradition. In my opinion, Jaeger-LeCoultre is the most important manufacturer of full-bridge handwinds today.

IWC calibre 9828 (above) demonstrates the ideal of full-bridge calibre design, with separate cocks for the balance, escape, and fourth wheels, a main bridge for the center and third wheels, and a bridge each for the mainspring barrel and crown wheel. This construction is elaborate and expensive for the manufacture to produce, but for the watchmaker in the field it is the easiest to service and repair. The artistic merits are self-evident, as every shape and space demands thought for proportion and continuity of design, and the finishing of every surface and edge are a measure of craftsmanship. It is the full-bridge more than any other top-plate design that allows the vision and skills of the designers and watchmakers to be expressed and displayed in full — and likewise any lack thereof.

It should be noted that it is somewhat uncommon for wristwatch calibres to use a six-bridge construction — though it is seen in many vintage IWC wristwatch movements like calibre 83 — rather even the most expensive handwinds tend to use a single bridge for mainspring barrel and crown wheel. Many of these five-bridge calibres represent the apex of wristwatch calibre design, as are
exemplified by the 10”’ and 12”’ calibres of mid to late 20th century Patek Philippe.

The full-bridge movement evolved in the age that preceded the invention of effective environmental protection for watch movements. In that time, it was common for the movement to be serviced annually and was thus imperative for the movement designer to create a movement that was very easy to service and repair — even at greater manufacturing cost. In time the full-bridge movement came to be a form of art in-itself, with simpler designs continuing to be used for economy watches.

It was the invention of the truly dust and water resistant case that began to lengthen service intervals and which also saw the practical application of automatic winding in a completely sealed watch. I suspect that what we think of simply as
water resistance, had not only a revolutionary effect upon the external design and uses of wristwatches, but also upon movement design —
beginning with a resimplification of top-plate construction. With service intervals stretching out to five years or more, and with automatic winding the norm rather than the exception,
infrequency and high labour cost of servicing ias resulted in very simple, practical, but inelegant top-plate designs.

While automatics like Patek Philippe calibre 27-460, and
Jager-LeCoultre calibre 920 show very classical full-bridge layouts, with great artistry in the shapes of their cocks and bridges, most automatics (whether integrated or modular) appear to dispense with such flourishes. At the very least, these movements show a conscious effort on the part of the designer to produce a beautiful and classical movement, all while moving forward technically into the worlds of bidirectional auto-winding (Patek 27-460) and ultrathin autowinding (JLC 920). While the latter movement does make the one compromise of joining the escape and fourth wheel bridges, it remains a solitary bastion of classicism within today’s world of auto-winding movements.

The extant group of four-bridge automatics is the relatively modern family of micro-rotor movements. Sadly there is little classical or modern in the execution of their top-plates. I feel that these movements represent a lost opportunity on the part of the movement designer, but I expect that the need for manufacturing simplicity has led to the use of shapeless, plate-like bridges that have become rather popular with watch consumers no doubt due to the broad expanse of flat decorated surface. What was once a design compromise has now become “art.”

The simplification of hand-wound calibres is taking form in the reintroduction of the 3/4 plate by the Glashutte manufactures A. Lange & Sohne and Glashutte Original. The simplicity of these new calibres with their large, lavishly decorated 3/4 plates has captured the imagination of many collectors of high end watches. While an antiquated design within the mechanical watch tradition, 3/4 plates at least represent a conscious choice on the part of the designer rather that the convenient compromises of the many three-bridge calibres seen today.

What I find disappointing about many current production movements is that they have neither the classicism of the full-bridge (or 3/4 plate), nor do they produce some new concept or aesthetic of design. I feel that this is the case for most automatics in production, and for some handwinds like Chopard’s new calibre 1.98 which, while a very complex movement finished to the Geneva Seal standard, is executed in a mere three bridges — one of which is the balance cock. There is
simply little conscious effort on behalf of beauty in calibre design going into these movements.

Despite all this gloom and doom there do remain a few classical full-bridge calibres among us. But they are the exclusive and expensive products of the Swiss manufactures, the best of which are the product of Patek Philippe and Audemars Piguet — two of the Great Three of old.

Patek Philippe calibre 215 PS (above) represents the best of modern designed and manufactured regular production handwinds, yet even it displays some compromises of design that are contrary to tradition, but which may be necessities of modern market economics. For instance, the layout of the calibre suggests a five-bridge design, but it is executed in four-bridges. Note not only the obvious joining of the escape and fourth wheel bridges into one, but the simplified shape of the main bridge as well.

A much newer calibre than the Patek Philippe pictured above it, Audemars Piguet calibre 3090 is wholly a product of the in-house designers at AP. This four-bridge top-plate design has been executed in rather unique way. The angularity of the bridge shapes which while distasteful to some, shows the proportion and even spacing so often lacking in modern calibres. You’ll note how the shape of each bridge is reflected in the shape of the bridges adjacent to it. At 20.8mm in diameter it is slightly smaller than the 215 PS (21.5mm), and at 2.8mm it is also
slightly thicker than the Patek’s 2.55mm.

This Twilight does not have to lead to a an eternal winter of full-bridge movements. Manufactures like Jaeger-LeCoultre, Audemars Piguet, and Patek Philippe, and masters like Philippe Dufour are striving to hold back the darkness for awhile longer. The new trend of in-house movement production means there is still a possibility that the full-bridge will find new expression. New evolutionary calibres like Patek Philippe’s calibre 28-20 and the yet unseen movements forthcoming from Vacheron Constantin hold some promise that a traditional form of the traditional art of mechanical watchmaking will not be permitted to fade into extinction.

Photo Credits:

Wanderer Above the Sea of Fog(1818), by Caspar David Friedrich (1774 – 1840); scan by
Mark Harden.
Calibre 11 by Philippe Dufour; scan modified by Mike Disher.
Lange calibre 8 3/4 x 12 by Gisbert A. Jospeh
IWC calibre 9828 by Roland Kammer
Audemars Piguet calibre 3090 by Mike Margolis
Used with Permission.

Copyright © 2000 Carlos A. Perez
All Rights Reserved