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Great buy! and some details...

June 14 2003 at 2:09 PM

Jaw  (Login TJN)

Response to Information on the Gran'Sport Chronographe

(Philippe Vandel, movement constructor)

Congrats to a wise purchase!

(The work of the hammer-lever, the control pawl and the jumper-spring of the column-wheel demonstrated the technical feat accomplished by calibre 829 in order to integrate the chronograph function - Mechanical manually-wound movement with retraograde chronograph function, 28,800vph, 36 jewels, 317 parts, 4.5mm high)

The Calibre 829 used in the 1996 limited edition is the most under-appreciated achievements of JLC, in my opinion.

(From left to right, at position 0, at position 10 minutes and at position 30 minutes - As the pivotal part of the chronograph mechanism, the cam driving the minute-counter called for extremely complex calculations)

("Pressing the lower pushpiece releases the hammer which, while pushing against the heart-piece returns the minute-counter wheel to zero. The latter in turn transmits the function to the opposite end of the movement. Thanks to an extremely complex principle based on a lever and spiral rack, which enables the minute-counter hand to return to its initial position" ~Manuel Guerin/Master Watchmaker on The Retrograde minute counter)

Movement constructor Philippe Vandel once described its 3 year development process as the most grueling. It was more arduous than the 1993 tourbillon development, according to Vandel.

The challenges are manifolds:
(1) The volume in the Grande Taille case was extremely limited for such a complication, and there was considerable difficulties in designing the integrated chrono movement to fit the case.

(The Chronograph mechanism in the"stop" position. The start/stop indication on the front)

(2) This movement was developed from scratch, many problems faced were then, new and the rich technical JLC archive could not provide the relevant details for research.

(The chronograph mechanism in the "start" position. These levers, gear-trains and heart-pieces handle the
chronograph functions. The column-wheel coordinates and syhchronises the lever movement)

(3) The retrograde 30 minute counter was particularly challenging for JLC and was a particularly important achievement in modern watchmaking in 1996.

(The technical drawing highlights the complexity of the rectangular chronograph movement)

(4) One of the many difficulties was trying to provide sufficient energy to its timekeeping and retrograde chronograph funcion.

(The Reverso Chronographe Retrograde brought together a maximum of functions within a minimum of space, thanks to the sophistication of JLC Calibre 829. The front displays various time measurements: hours, minutes and date as well as the start/stop chronograph indication. The back is reserved for chronograph functions, with a 60-second counter and retrograde 30 minute counter.)

If properly marketed, the 1996 limited edition ought to have done a "Datograph" to the industry, but was not sufficiently appreciated in my opinion.

(Gear-train driving the seconds counter and the retrograde minutes counter)

Although the 500 pieces were finally sold, and the Gran'Sport Chronographe relaunch is still a selling model. The 2 watches are not shown the proper respect they deserved. And despite the 1998 re-launch, I SUSPECT MJLC has not recovered the full development cost.

(Mechanical manually-wound movement with retrograde chronograph function, centre seconds and date, 28,800vph, 38 jewels, 317 parts, 4.5mm high)

The basic difference of Calibre 829 and 859 is that the chrographe seconds and minute counter are integrated with the Calibre 829 itself.

(Reverso Gran'Sport Chronographe houses calibre 859 by JLC, a masterpiece of watchmaking trradition embodied in a mechanical manually-wound movement)

The price for both the limited edition chrono and the Gran'Sport version are high in absolute term, but CHEAP in my opinion.


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