At the Geneva Salon in January, A. Lange & Söhne presented the fifth watch with the appellation “Pour le Mérite”. It unites five complications and pays tribute to classic watchmaking as a paragon of true perfection. Given the numerous complex mechanisms, the assembly of the 684-part manufacture calibre is a formidable challenge. Only the best watchmakers can put together the individual subsystems with the precision required for them to interact flawlessly in the end.
“Substance over semblance” is the underlying motto of the Tourbograph Perpetual “Pour le Mérite”. Two of its five complications serve the sole purpose of improving rate accuracy. The fusée-and-chain mechanism ensures the smooth flow of torque from the mainspring barrel to the balance. Isolated from the influence of gravity, it oscillates inside the rotating tourbillon cage. The split-seconds chronograph is controlled in the classic manner with two column wheels. In a space-saving configuration, the module for the analogue perpetual calendar is built around the tourbillon.
The assembly of the movement is a venture of much greater complexity than meets the eye. “The harmonious interaction of the five complications does not even begin to do justice to the amount of work involved,” says Anthony de Haas, Director of Product Development at A. Lange & Söhne. In fact, no two assembly processes are alike. “Even if each of the 684 parts is manufactured strictly within the micrometre tolerance range, the watchmaker still has to perform many minute adjustments to ensure that all the mechanisms work together perfectly as envisaged by the calibre engineers,” de Haas muses. He adds: “On the part of the watchmakers, this calls for the utmost of technical comprehension, experience based knowledge, manual virtuosity and virtually infinite patience.”
The images in the gallery capture a few decisive work steps out of several hundred.