When a watch is developed at A. Lange & Söhne, the objective is always to create a timekeeping instrument with outstanding functionality. Ferdinand A. Lange was already committed to the quest for the "perfect watch" and today, each timepiece is still built with the determination to improve its precision, enhance its legibility, or refine its convenience. But there's more to an A. Lange & Söhne watch than technical perfection: each movement must live up to the highest aesthetic expectations as well. Every timepiece is endowed with characteristic traditional elements such as the engraved balance cock, screwed gold chatons, and untreated German silver plates.
It is the prototyping shop that first breathes life into the blueprints of the calibre engineers. Each new component is individually crafted by hand. The resulting prototypes are used to test the long-term functional integrity of all mechanisms and to review every single detail, no matter how seemingly insignificant. But extensive testing is not just a phase at the beginning of the development process: each timepiece is also exhaustively inspected before it is handed over to the customer.
All quality-relevant movement parts are crafted in-house at A. Lange & Söhne. Parts production begins with the fabrication of the blanks for plates, bridges, levers, springs, wheels, and pinions. Subsequently, all boreholes and edges of the parts are deburred by hand and subjected to precise optical measurements: the main plate alone is scanned at several hundred points that are verified with an accuracy in the order of a ten-thousandth of a millimetre.
Watch connoisseurs can identify an A. Lange & Söhne movement at first sight. Each component is decorated with its own specific type of finissage, whether or not it is visible through the sapphire-crystal caseback. No matter how small it might be, each part must comply with rigorous artisanal and aesthetic standards. It takes several months of practice just to perfectly execute a flat polished finish, and in chamfering, great emphasis is placed on assuring that the edges are not only bevelled to the same angle but also to the same width. A special type of finish is reserved for the balance cock: it is engraved with the Lange-style floral pattern that makes each Lange watch unique.
During the first assembly, the main focus is on the smooth interaction of the complex mechanisms of the movements which consist of several hundred parts. Although they already function flawlessly at this point, all movements are taken apart and cleaned again after the first assembly pass. This is because even with utmost care, it cannot be ruled out that a component was slightly scratched during the adjustment phase or that tiny dust particles may have entered the movement. After they have been cleaned, many of the filigreed parts are decorated, engraved, and polished with traditional techniques. Uniquely in the realm of horology, this time-consuming second assembly process is performed with every watch, without exception.