The Audemars Piguet Calibre 3090

The Audemars Piguet Jules Audemars Handwind

featuring the Calibre 3090 movement

Version 5
by ei8htohms
© 01-15-2002

(click on all images to view a larger version)
Jules Audemars handwind in white gold with Le Brassus waves dial


If the early nineties convinced the watch industry that mechanical horology was not dead, the late nineties saw many watch manufacturers seeking to redefine themselves in light of this startling realization. While it was enough for many companies surviving the dark period of the quartz revolution to simply put a case and dial on a third party ebauche, it didn't take long before a better informed consumer was able to form an opinion about the difference between an assembler of watches (etablisseur) and a true manufacturer (manufacture). Although there are many subtle distinctions in this apparent dichotomy that are lost on most, producing one or more movements in-house clearly places a manufacturer on a different level altogether.

Designing, prototyping, testing, tooling up and ultimately manufacturing a movement is no small undertaking. While the mere act of developing an in-house movement says much about the company that does so, the design and execution of the end product make an even more profound statement. Intentions that are hardly discernible from a company's implementation of a third party ebauche are clearly evident in a movement developed and produced in-house. With this commitment of many thousands of man-hours of skilled labor and resources, a company's heart and soul is poured into the endeavor and much can be gleaned about their priorities by carefully examining the fruits of their labors. In the course of this article we will attempt to understand what Audemars Piguet is telling us through the design and execution of the calibre 3090 simple handwind.

The Clothing

The Jules Audemars slender profile is appropriate to the 2.8 mm height of the Cal. 3090

Audemars Piguet has long been held in the highest esteem for their tour-de-force, high horology timepieces while never shying away from a bold design. The Royal Oak, for instance, is hardly less eye-catching 30 years after its release, amidst droves of derivative designs from other companies. It and the Millenary line are all the more daring when contrasted with the more restrained and classical Edward Piguet and Jules Audemars lines.

The first incarnation of the calibre 3090 is housed in the beautiful Jules Audemars case. Do not let its classic beauty fool you. Even at 36 millimeters in diameter, this case is an advanced construction that owes much to the Royal Oak. It shares a simpler use of contrasting finishes (implementing two instead of the five found in the Royal Oak) that are executed to near perfection. The horizontal brushing of the case band ends abruptly at the vertical brushing on the sides of the lugs and contrasts sharply with the mirror polish of the bezel and the tops of the lugs. The beautiful and striking combination of brushed and high polished surfaces, found in many Audemars Piguet designs, only hints at the similarities though. When the six white gold screws are removed from the display back of the case, it can be seen that the fundamental construction borrows heavily from the Royal Oak. These six screws are not merely holding the back on, rather they extend all the way through the case band and into the bezel, holding all three pieces of the case [4] together in a very sturdy, highly water resistant fashion.

The crown is signed with the AP logo The advanced construction of the three piece case

The diplay back secured with six white gold screws.

Although quite beautiful, the decorative finish of the movement when viewed through the sapphire display back left concerns in my mind about what would be encountered within. The delicate anglage of the screw heads and slots, as well as the high polished chamfering of their holes [5] fit perfectly with the gentle Le Brassus waves of the bridges. In addition, the yellow gold filled engravings were executed to the highest standards. I did, however, find the finish to be lacking in the consistency of the hand applied anglage on the bridges themselves. Here and there it was very finely applied (although not exquisitely), but other spots showed wavy lines and imperfections I would not have expected in a movement of this quality [6]. I also didn't care for the unfinished spring on the escape wheel cap jewel [7], especially in such close proximity to the more finished Kif spring on the balance jewels [6] . This is consistent with this type of spring though, and is not a fault of this particular implementation.

When removing the movement and dial from the case band, it was possible to admire the solid spacer ring [8] used to secure the 9 ligne (20.8 millimeter) movement inside the 36 millimeter case. Like all the other aspects of the case, it was elaborately conceived and wonderfully executed, securing the movement from the back while attached firmly to the case band by three screws under the bezel.

The lovely treatment of the screwhead and countersink The nicely finished Kif spring and mediocre anglage The unfinished spring on the escape wheel cap jewel The spacer ring, secured from the front of the case band

The dial of this watch is a work of art [9]. The finely frosted outer ring, punctuated by flawlessly applied white gold Roman numerals, is set off from the central portion of the dial by delicate, ridged guilloche work (guillochage). The centerpiece of the design is the creamy Le Brassus waves, surrounding and setting off the sunken sub-seconds track and moated rectangular Audemars Piguet hallmark. The white gold leaf hands are perfectly proportioned and well executed and complement the classical aesthetic of the rest of the dial. I did have reservations about the painted second hand, as the quality of the painting was not perfect and seemed a little out of place. The overall effect was still one of ethereal beauty, enhanced by examining the dial outside of the confines of the case.

The Movement

Upon removing the hands and dial, the thoroughbred qualities of the movement are brought clearly into focus. Contrary to the "display back finish" that is all too common in the watch industry today, the execution of the bottom plate [10] is superior to the finish of the bridges visible through the display back. Although I can't guess at the reasons for the differences, the anglage under the dial [11] was superior to the more visible anglage of the bridges in every regard. In addition, the perlage was nicely applied and the screw heads and holes were treated as well as the bridge screws in all respects.

The most undeniable sign of quality was the deliciously executed keyless works [12]. The quality of steel work is always telling as it takes more time to properly finish steel than any other metal found in a watch and no effort was spared in creating the keyless works in the Audemars Piguet calibre 3090. The set lever, clutch lever and detent were all beautifully grained on top and high polished on the bottom with perfectly straight functional edges and mirror polished anglage on the non-functional edges. This is the ideal execution of keyless levers as it maximizes the contacting surfaces for optimal reliability and minimal wear while aesthetically enhancing the non-functional edges and removing the possibility of burrs or scarring. Levers of this type are more time consuming, and therefore expensive, to manufacture than stamped or tumbled levers and the fact that they are beautifully detailed in a typically hidden part of the movement is the hallmark of a deeply ingrained commitment to quality.

The movement from the dial side The superior anglage under the dial The beautiful steel work of the keyless levers The architecture of the Cal. 3090

Structurally speaking, the calibre 3090 has a fairly traditional bridge layout [13] with one notable exception: the bridged balance assembly. The bridge design is a bit of a departure for Audemars Piguet aesthetically. It is not derivative of their early pocket watch designs nor does it borrow heavily from the Jaeger LeCoultre base movements AP has been using in recent years. The horological architecture from the Vallee de Joux is typically slightly more angular than the work from Geneva while not as severe as that of the Saxon Glashuette style. While the bridge layout is very French-Swiss in appearance, the elaborate scalloping seems slightly self-conscious, as if the designers were not quite sure how to properly integrate the balance bridge. That said, it is a beautiful and highly functional layout, and little touches like a separate escape wheel cock make it clear that it was designed by watchmakers with watchmakers in mind.

The nicely finished power train

With the barrel bridge and power train bridge removed, Audemars Piguet's relentless pursuit of excellence becomes even more apparent. The barrel has two concentric mirror-polished surfaces separating the three brushed rings; the two inner rings are brushed radially while the outermost has a spiral pattern. To my amazement, this same pattern is repeated identically on the bottom of the barrel [14] and the inside of the barrel is mirror polished throughout [15] . The mirror polishing inside the barrel is more than simply beautiful, it also insures a perfectly smooth power flow during the unwinding of the mainspring. Such attention to detail lavished on the most fundamental component of the movement is as refreshing as it is uncommon.

The train wheels also have a mirror polished ring separating the two circular brushed sections and a delicate anglage on the spokes, hub and the inner edge of the rim [16]. The teeth of the power train wheels are all epicycloidal with round troughs and are well polished as are the pinion leaves. All the pivots are of course perfectly polished and their bearings are jeweled, including the barrel. I could find nothing that could be improved upon in the power train and was deeply impressed with the functional and decorative finish throughout.

The bottom of the barrel (only literally) The inside of the mainspring barrel A nicely finished power train wheel

The Escapement

The escapement of the Cal. 3090

At this point, let us consider the heart of the watch: the escapement and balance. The free-sprung, adjustable mass balance and flat Nivarox 1 hairspring beat at a leisurely 19,800 vibrations per hour. While the rest of the movement is largely traditional in its design, as we approach the balance itself, the traditional elements begin to be overshadowed by some high-tech performance-enhancing features.

The escape wheel and pallet fork appear typical of modern high-end watches: they are nicely finished if lacking the elegance and elaboration of their counterparts of fifty years ago. The pallet bridge is a nicely made circular shape [17] and the adjustable mass, Glucydur balance (with eight movable collets) [18] is supported by a sturdy balance bridge, which features an equally secure locking stud carrier. While most fine watches rely on a balance cock, supported on only one side by a single screw, Audemars Piguet opted for a much more rugged construction. This alludes to their intention to use variations of this movement in sports watches as well (they are reportedly working on an automatic version already). The locking stud carrier [19] can be adjusted and locked down via two small screws on top of the balance bridge. This allows for precise adjustment of the beat of the escapement (the symmetry of the tick and the tock) but can be secured so that the adjustment will not be disturbed by shocks. Such a precise and elaborate method of adjusting the beat is all the more appropriate in light of the free-sprung balance, where there are no regulator pins to alter the beat in the slightest during rate adjustment.

Circular pallet bridge The balance The underside of the balance bridge with the beat adjustment mechanism The laser welded collet

The traditional "Geneva stud" is a circular hairspring stud secured under a high-polished, kidney shaped plate with two screws. The methods of attaching the hairspring to the stud and collet are, however, decidedly modern approaches. Traditionally, the hairspring is fed through holes in the stud and collet and held in place with tiny tapered brass pins. The problem with the traditional method is that the pressure of the pin on the spring distorts it somewhat and changes the modulus of elasticity in close proximity to the pinning points. In addition, the hairspring must be bent rather profoundly from where it exits the collet before it joins the concentric, regular spiral of the rest of the spring. The shape of the innermost coil of the hairspring is then a source for much variability in the fine timing adjustment of the watch.

The calibre 3090 instead uses a very modern Nivatronic collet [20] that is shaped like a muted cross. The hairspring is laser-welded to one of the lobes of the collet without deforming the elasticity of the spring or its curvature in relation to the rest of the spiral. This solid collet is also better poised than the split variety although it is not as easy to turn for gross beat adjustments. The outermost coil of the hairspring has a rather severe dogleg where it attaches to the stud as has been determined to improve positional performance and isochronism.

The method of attaching the hairspring to the stud is also quite modern. It is cemented in place with a reddish pink "hot-glue." This glue holds the hairspring firmly in place without distorting it and can be adjusted if necessary using hot tweezers. Both methods of attachment (hot-gluing and laser-welding) are superior from a performance standpoint although some might fault them for being less expensive and less traditional. They are, however, widely used in modern, high-grade watches and seem to be the accepted standard. All of the many features of the escapement and balance indicate a commitment to maximum accuracy while the bridged balance and locking stud carrier insure maximum robustness.


The extruded crystal gasket

While I do not put much stock in a brand new watch's performance, I found this example to show a loss of between one and three seconds in all positions although it's impossible to say how being worn might affect its rate. It is worth noting that I found some minor flaws in the printing of the dial and the execution of the hour hand at high magnification and, most noticeably, the gasket around the crystal was partially extruded near the ten o'clock marker [21]. Such sample to sample oversights are sadly not uncommon in watches at this level but I would like to see Audemars Piguet rise above the competition in this regard as well.

Taken as a whole, the Audemars Piguet calibre 3090 is a beautiful piece of work. I found it to be a joy to work on; the perfect fit of the bridges and screws made removing and replacing them effortless. Other than some minor deficiencies in the visible anglage it is an exquisitely well crafted movement. Although there is something delicious about this subversion of the "display back finish" phenomenon, it is hard to imagine it is an intentional design element. The 3090 is at times very traditional, but without any sacrifices of robustness or performance in the crucial features surrounding the escapement and balance. On the contrary, it is boldly divergent from tradition in these regards, sacrificing only superfluous craft in favor of technological advancement.

It seems fitting to me that the signals emanating from this, the first simple construction from Audemars Piguet in some time, are not simple at all. How could this anchor of their more basic model range stand alongside the audacious complexity of their technological powerhouses if it were not in itself somewhat conflicted? It is a design and execution as rife with complexity as the company itself. If this movement is indicative of future directions for Audemars Piguet, the future looks very bright indeed.



The following will likely be included in subsequent revisions of this article - 

First, the tactile feel of manually winding this watch is exquisite. The perfectly polished winding pinion and crown wheel give it a creamy smoothness that is second to none. ThomasM has assured me that he finds the sample to sample consistency of the winding feel of the 3090 to be the best he's found. 

Secondly, I wanted to mention that since the article was released, we have it on good authority that the finish of the bridges now matches the level of the finish of the bottom plate.  JD

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Copyright January 2002 - Mr. John Davis and - all rights reserved