Introduction
This page retains the material used to explain and catalogue the original Frederique Constant perpetual calendar in addition to the new limited edition developed by The Naked Watchmaker.
The example shown in these images is the prototype.
The original Reason for deconstructing this watch
A simplified perpetual calendar retaining classical elements made in an industrial execution, whilst assuring a solid construction built for longevity.
Introduction/functions
The FC-775 calibre was developed by Manuel Da Silva Matos, R&D director, and Pim Koeslag, ex-technical director of Frederique Constant, over a three year period and was launched in 2016.
It displays hours, minutes, moon-phases, date, day, month and leap year. Once programmed the mechanism will take into account the months with 30 and 31 days, the 28 days of February and also the leap year cycle with the return of 29 February every four years.
The original perpetual calendar model
Frederique Constant QP dial view
Frederique Constant QP case back view
Frederique Constant/The Naked Watchmaker collaboration
The design concept was to open the dial in order to view the technical aspects of the perpetual calendar following the deconstruction that had been originally executed, and is shown below. In addition, improving the overall readability of the different indications of the calendar, and altering the leap year indication into a more contemporary system.
Limited edition of 99 pieces
Prototype model photographed
Despite increasing the thickness of the dial and adding complexity through the change of leap year indication, there was sufficient space under the sapphire so as not to require any changes to the original case and the overall thickness of the watch remains the same as with the original model
The cutouts in the dial allow for the components and decoration to be viewed and accentuate the three-dimensional mechanics of the mechanism.
The hands were designed to be easily seen but not to block the visibility of the mechanics of the QP the reason for their cut outs and the wide design with white lacquered finish.
Technical Specifications
Frederique Constant own QP manufactured FC-775 calibre. Frequency of 4 HZ (28’8000 vibrations per hour), 26 jewels, 38-hour power reserve. The diameter of the movement is 30 mm and 6.7 mm thick. The movement is made of 191 parts.
Polished stainless steel 3-parts case, diameter of 42 mm, 10.2mm total thickness. Convex sapphire crystal, See through sapphire back. Water-resistant to 3 ATM.
The leap year indication (below) was designed to avoid the months indication being obstructed in any way by an additional hand, the years are shown through an opening at February, each year is a different colour and the leap year is red. Year 1 : white, year 2 : yellow, year 3 : black, year 4 : red.
The Months indications are altered to optimise their visibility using a combination of letters, dots and numbers of the month The year hand was removed and a colour indication has been placed between January and March. The leap year is red.
The Moon phase was altered to become an animation reflecting the movement of time and shows the two moons when one is usually hidden. This created with the SLN moons gives a visually different use of the moon disk.
The Day and Date subsidiary-dials and hands are larger than the original Frédérique Constant dials, providing greater visual visibility.
The use of SLN links to vintage watches as well as providing visibility at night.
The blue bridge colour is for contrast with the steel and gold coloured components to emphasise the mechanics. Blue also traditionally holds a special place in the world of horology linking with blued steel hands and screws.
The brown of the dial was used to generate a vintage feel for a classical watch. It also allows the indications in white to be strongly contrasted along with the hands- It is also congruent with the choice of strap.
GALLERY
In the grid below are both images used in the description of this page plus more. Please click on the image to enlarge and see in full.
The original perpetual calendar model
Profile images
Frederique Constant QP 3 o’clock, crown side
Correcting the QP
Correctors, at 5 o’clock advances the moonphase, at 8 o’clock is used for the day of the week, at 10 o’clock advances the day and date simultaneously. Above the day and date is the month corrector.
When programming the calendar, first the date is set then, the day (because the day can be set independently of the date). To finish, the button near 11 o’clock corrects the month and the leap year at the same time. The hour and minute functions are adjustable through the crown.
The case back screws clock-wise onto the case centre and is removed with a six fingered key. A large circular rubber seal sits in a gulley running around the inner case (here not shown) and is compressed by the case-back when screwed in place.
Frederique Constant QP Case back removed. The movement is held in place by two blued screws with casing bridals.
The bezel removed. When assembled the bezel is pushed tightly onto the centre of the case, a special tool with a knife edge is used to remove it when dismantling the watch.
Frederique Constant QP The bezel is removed to allow the movement and dial assembly to be released from the front of the case centre.
The movement and dial assembly removed from the case centre.
Frederique Constant QP The winding crown has been replaced, when removing the assembly from the case the stem is pulled out.
Movement assembly removed from case.
Hands removed from movement.
Dial removed from movement.
Frederique Constant QP Hands
The dial removed and the perpetual calendar module in full view. The two blued screws lock the module on to the movement.
Frederique Constant QP All levers and springs are made from steel, the wheels and mainplate from brass.
The brain of the perpetual calendar.
Frederique Constant QP The large straight grained lever is the principle operating lever. The steel snail at 3 o’clock sits on the date wheel and gathers the days at the end of each month, pushed by the beak sitting on the operating lever.
Frederique Constant QP The circular steel cam (normally hidden by the hand that points to the leap year) rotates once a year and dictates the number of days gathered at the end of each month. The deepest trough in the wheel is for 28 days.
Frederique Constant QP The cam sandwiched between the two yellow wheels reduces the number of days gathered every 4 years on February, to 29 days to provide the leap year.
The day star wheel, moon-phases disc, month cam and date wheel (with snail) removed.
Frederique Constant QP One of the differentiating factors of this QP is the ease of assembly and overall simplicity of design.
Close up of the three steel pieces shown above. The first is the date wheel with the snail cam held in place by two steel pins, the date hand sits on the centre chimney. Lower left is the month cam upon which the month hand is pushed and the day star wheel that carries the day hand.
Frederique Constant QP Each piece sits on a polished steel post that is riveted into the main-plate of the module.
The beak or nose of the main operating lever is close to the highest point on the lifting cam, sitting on the closest yellow wheel that meshes with the hour wheel driving the calendar mechanism.
Frederique Constant QP The straight graining on the surfaces of the steel pieces is executed manually.
The steel lifting cam, (shown partially removed) is pushed around by the pin to its left, that is riveted into the wheel.
Frederique Constant QP The steel lifting cam against which the operating lever pushes is lightly greased on the canon it sits, as well as the contact surface with the operating lever.
The angle on the lifting cam (shaded black) allows for the setting to be turned anticlockwise and for the cam so slide over the pin that drives it, preventing any damage. The long spring to the right, holds the cam in place, but allowing it to lift when needed.
Frederique Constant QP The system is over 200 years old, but works as effectively today as it did two centry’s ago.
The Perpetual Calendar module sits on the automatic calibre to its left.
Frederique Constant QP The movement and module sit directly in to the case centre with no movement ring.
The ‘Ant Eater’ shaped principle operating lever.
Frederique Constant QP The beryllium copper tube in the centre is the pivoting point for the lever. It sits on a threaded steel tube pushed into the main-plate of the module. The mix of polished steel and beryllium copper result in a smooth low friction, auto-lubricating contact between the two pieces. The diameter of the tubes are large to ensure the lever remains flat once held in place by its holding screw, avoiding any unwanted diagonal play.
The two steel indexing levers centre and left for the date and leap year wheels. On the right the manual corrector for the moon phases wheel.
Frederique Constant QP The indexing levers and springs are incorporated into one piece to simplify assembly and reduce the quantity of components.
Below, the indexing lever-spring when armed, butts against the risen section of the module main-plate.
Frederique Constant QP
Frederique Constant QP
The manual correctors for programming the module. On the left for the year cam, and centre for the principle operating lever.
Frederique Constant QP The external case pushers act on the vertical pillars.
The corrector on the left for the year cam, pivots. The central corrector, for the operating lever slides in and out in a groove milled into the main-plate.
Frederique Constant QP Inclined view of the correctors activated by the case pushers situated at the 9 o’clock side of the case.
The large central brass wheel is the hour wheel upon which the hour hand is pushed. The brass upper pinion sitting on it, drives the perpetual calendar mechanism.
Frederique Constant QP The setting mechanism in view.
Frederique Constant QP The vertical steel post is the canon pinion upon which the minute hand is placed.
The Frederique Constant calibre FC-100, automatic. Intergrated with the perpetual calendar becomes the FC-775.
Frederique Constant QP The rotor held by a single screw, sits on a large bridge held in place by 3 blued screws and covers the majority of the train.
The rotor removed, showing the full automatic bridge with Pearlage (Spotting) & Circular Côtes de Genève decoration.
Frederique Constant QP The rotor has a steel ball race placed in its centre. The pinion around the ball race (hidden) meshes with the two beryllium copper wheels partially viewed in the centre of the automatic bridge. The rotor weight winds as it moves both clock wise and anti-clockwise.
The rotor removed and the movement inclined. On the side of the movement below the balance is a milled-out section allowing visibility to view and check the lateral adjustment of the balance and escapement when the watch is assembled.
Frederique Constant QP The balance pivots are protected by Incablock shock protection.
The automatic assembly removed revealing the large balance, going train and barrel bridges.
Frederique Constant QP The entire automatic mechanism is integrated into the underside of the automatic bridge. The last wheel in the automatic bridge train meshes with the ratchet wheel winding the barrel arbor and mainspring.
The balance bridge and assembly removed allowing access to the escapement.
Frederique Constant QP The large screws on the winding mechanism ensure the large steel wheels/pinions easily remain flat.
The train bridge removed showing the gear wheels.
Frederique Constant QP The large flat surfaces between the bridges and main-plate assure a solid/rigid and clean assembly and construction.
The Swiss anchor and its bridge removed.
Frederique Constant QP Although there is an oil sink in the Swiss anchor bridge, this jewel is usually not lubricated.
Frederique Constant QP exploded view
Summary
The calibre from the base movement through to the perpetual calendar module is solid, strong and simple in construction. Disassembly, as well as assembly, is amongst the most straightforward and logical of any QP visited so far by The Naked Watchmaker, ensuring simplicity in after-sales service.
The mechanism is both robust and easy to set up with safety mechanisms built-in, to avoid damage when programming it. The only proviso here, regarding set up, is the need to set the watch to 12 o'clock midday before making the adjustments (as with the majority of calendar mechanisms).
To learn more about Frederique Constant