The Reason
The first chronograph from the new collection of watches, Code 11.59 by Audemars Piguet to carry their newly developed calibre 4401.
Functions
Automatic winding, fly-back chronograph, with hour counter (at 3 o'clock), minute counter (at 9 o'clock), constant small seconds counter (at 6 o'clock), instantaneous jumping date indication (at 4.30), hour and minute display.
At the top of the image on the case back surface are the hallmarks that include the carat of the gold, AU750 (18k), the makers stamp and the official stamps of the Swiss assay office.
Technical Specifications
Movement calibre 4401, thickness 6.8 mm, diameter 32 mm. Number of Jewels 40. Number of components 367. 22 carat rotor weight with bi-directional winding. Minimum power reserve 70 h. Frequency 4Hz, (28,800 VPH). Free sprung balance with inertia weights for regulation. The case is 18 carat red gold, 41 mm in diameter, 12.6 mm thick and water resistant to 3 atmospheres (30 m).
Please move the cursor across the image below, (or by finger on a smart phone), to rotate the watch.
Viewed face on, the case and shoulders are simple and classical in design. As the watch is tilted the shoulders are seen to be cut away to allow the central octagonal middle of the case to be accentuated. The recessed octagonal middle is sandwiched between the round bezel and the case back, and all three parts are separate in the construction. The sapphire is more complex than conventional examples and although visibly round when viewed face on, the form is convex on the outside and concave on the interior, with a curve from 12 o'clock to 6 o’clock.
The pushers are positioned into the flats of the octagonal shaped middle. The winding crown has 8 facets associating to the octagon form.
The curved sapphire viewed from the profile.
The large surfaces of the case are either circular or straight grained. All angles are polished. The large angles on the octagon middle case required that this section was separate from the bezel and case back (as well as the shoulders), to be able to polish them in order to accentuate the complex octagonal forms.
The dial sits flush onto the movement. The tachymeter scale sits above the dial and the hands turn below the tachymeter’s surface adding to the three dimensional effect when the watch is tilted.
The case back is held in place by 5 screws. Each screw traverses the centre of the case and is fixed into the bezel. The bezel is initially held by 2 screws hidden under the case back, once the case back is in place all 7 screws hold the watch case assembly together.
The strap is held on a stainless steel bar with balance staff shaped pivots. These turn in the holes machined into the hexagonal headed shoulder screws. To remove the strap, both screws are unscrewed.
The shoulders are fixed onto the bezel. The lower section of the shoulder is a close fit to the case back when it is in place, close to the thickness of a sheet of paper between them. The strength of the design was observatory tested to guarantee the solidity of construction.
All of the edges around the shoulders are beveled and polished by hand.
There is no movement ring between the calibre and the inner case due to the calibre’s large diameter and the cases’s thick walls. The mass of the walls allow space for the various seals making the case water resistant and providing space for the case screws.
Most surfaces, seen and unseen are decorated.
Audemars Piguet movement calibre 4401
The dial removed from the movement. All of the batons/indexes and numbers are made in gold and riveted in place. The black surface of the dial is the result of seven layers of lacquer.
The lower surfaces of the subsidiary dials are matt finished to accentuate contrast with the hands. The black surface of the dial is the result of a minimum of seven layers of lacquer, varying depending on colour and batch.
The gold brand name is made in two pieces and riveted in place. The process of development for it, took in excess of a year to perfect.
18 carat red gold hands matching the case and rotor weight.
The rotor weight removed, showing the full view of the calibre. The small yellow wheel to the left of centre, is the first to be driven by the rotor weight pinion.
The central cam/column wheel that controls the levers and springs of the chronograph mechanism, activated by the user via an operating lever touching the 2 o’clock pusher.
The 22carat red gold rotor. Skeletonized to improve visual access to the chronograph mechanism.
The ball race contains ceramic beads/balls which do not require lubrication and run more smoothly and quietly than traditional steel versions.
The balance bridge holds the balance assembly between it and the mainplate, pivoting in Incabloc shock protection.
The balance spring is held in the triangular shaped polished steel stud that is in turn held in place on the balance bridge by the friction of the double sided thumb spring stud holder. The length of the material around the ‘thumbs’ allows for the elasticity needed to assure the steel stud is held tightly in place, but be adjusted by the watchmaker who regulates the watch. This assembly can rotate slightly to adjust the balance wheel in beat with the Swiss anchor.
The balance bridge removed.
The nuts that are screwed to the pillars upon which the balance bridge sits, can be adjusted to easily alter the end shake of the balance staff, with out altering the position of the shock protection in the balance cock.
Recto-verso of the balance bridge with free-sprung balance wheel. 6 maslots/inertia blocks are adjusted for regulation. (A free-sprung balance does not have an index adjusting the effective length of the balance spring for regulation purposes. This improves the overall isochronism of the watch).
The Swiss anchor and its bridge removed.
The first series of chronograph springs and levers removed.
The upper chronograph bridge removed (that also supports the rotor weight).
Construction and design is always important, but each following step is as relevant as the one it precedes. The clean production and silky machined finish of the under surfaces shown here, represent the level of attention to the components from the moment they leave the machine.
Continuing to dismantle the movement, once the upper bridge is removed access is given to the chronograph wheels and vertical clutch mechanism, plus the main operating lever which turns the column wheel.
The three chronograph wheels that carry the chronograph seconds hand (to the right) and the minute and hour recorder hands to the left.
The large steel discs (on the two wheels to the left) are acted upon by the chronograph braking levers.
The vertical clutch mechanism. The cone when pushed down deactivates the mechanism, when it is released it rises and the chronograph runs.
The bridge that holds the hammers and hammer springs in place removed.
The hammer springs and levers and below them the operating lever that drives the hammers.
The pillar/column wheel, indexed in place with a lever and spring.
The majority of the chronograph mechanism removed, leaving the going and automatic trains in place.
The automatic train bridges removed.
The automatic train wheels and drive pinion removed.
The two steel reverser wheels with (ceramic) ball races.
The train bridges removed revealing the barrel, ratchet wheel and going train.
Recto-verso of the train bridge.
The movement dismantled with the centre wheel still in place.
The dial-side of the movement.
The cam in the form of a cross is linked with the rapid date change and pushes the disc around when the stem is turned in the first pulled position of the winding crown.
The pawl set between 20 and 21 indexes the disc.
The date disc is held in place by 3 plugs that allow the disc to be removed without dismantling the complete calendar mechanism.
The large yellow wheel drives the operating lever that moves the date disc.
The date disc removed leaving the calendar and setting mechanism in place.
The cover plate for the calendar mechanism removed.
The date disc, with internal teeth form, cut to allow for minimum friction when the disc jumps and a solid ‘stop’ once indexed.
The indexing pawl for the date disc.
The operating lever with detent system that pushes the date disc.
The hack/brake system for the balance wheel can be seen at the outer side of the wheel train between 6 & 10 o’clock. Linked with the setting mechanism.
The underside of the drive wheel carries the cam that the operating lever with detent pushes against.
The nose of the cam can be viewed through the hole in the wheel. The screw with three slots tightens anti-clockwise.
The operating lever with detent system in full view. The cam on the drive wheel pushes the lever until the detent falls onto the other side of the date disc tooth, before it is released and instantly jumps the date.
The setting mechanism plate removed.
During the process of manufacturing the watches there are tailor-made containers produced to store and transport the components. Special movement and case holders are routinely made to ensure the watches are easily and safely manipulated. Below are the boxes used to store and transport the lacquered dials. The boxes are a reused.
The box containing the dial with dial claw.
The inner dial claw allows the dial to be removed from its outer box by the central column. Then by pinching the two outer elliptical columns the dial is released.
Before the movement is cased, it is tested in a plastic container with a working dial and hands until it has passed the various imposed tests. The tests include the chronometry of the time-keeping, the functionality of the chronograph, the automatic mechanism and the power-reserve with the chronograph activated.
Prior to a definitive winding crown a working brass one is used.
The working rotor in tungsten is used to test the watch prior to casing. Then it is removed and replaced with the definitive 22 carat version once the movement is cased up.
Summary
As with the previous deconstruction of the hour, minute and seconds version, calibre 4302 of the Code 11.59, when first viewing the aesthetics of the watch face on, the immediate effect is of a simple and modern designed chronograph. When the watch is tilted a different effect is generated, principally from the curved sapphire, octagonal centre and milled out shoulders. The result is a design with a contemporary, technical construction. Simple elements such as the sapphire and the system for holding the strap in position have been re-invented. The watch is a combination of diverse elements, assembled congruently to make an original contemporary chronograph.
The calibre follows the same philosophy as was adopted for the case, classic in function but updated in its conceptional approach. The calibre is larger in diameter than AP have conventionally used and is a fully integrated, vertical clutch chronograph. Manufactured by the brand, it is solid, accurate, aesthetically balanced and well thought through.
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The act of dismantling the watch with out any prior explanation or aid, was simple and logical despite the complexity of the piece.
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