What makes a watch even more exclusive? One factor is the finishes lavished on its movement, especially if they’re handcrafted. A. Lange & Söhne decorates especially beautifully. In this visit to the WatchTime Archives, we a look at the Saxon manufacture’s famed finishing techniques.
The hand-engraved balance cock is a Glashütte specialty that’s still mastered and practiced by only a few brands in Germany’s watchmaking mecca. The surface of this component is usually decorated with floral ornaments. The engravings are usually inlaid with gold. For the special model to celebrate the 25th birthday of the Lange 1, the engravers integrated the number 25 in the style of the famous Lange Big Date and painted the engravings blue, which is the anniversary color. The spring in the swan’s neck fine adjustment mechanism and the cover plate of the escape wheel are given a flat polish by manually moving the components in a figure eight pattern for two hours while pressing them against various diamond-coated polishing foils.
The Glashütte sunburst is another local specialty. It’s used on the ratchet wheel and crown wheel. This decoration consists of fine lines that radiate from the center toward the periphery. Unlike a conventional sunburst finish, the rays are curved rather than being straight or nearly straight. The strokes are either continuous or subdivided into several concentric rings. In both variations, the reflections on the surface seem to move in a circle when the incident light changes. A Glashütte sunburst is created when the workpiece and the polishing wheel used for production rotate in opposite directions. As on the caliber of the new Zeitwerk Date, the plate is decorated with a Glashütte banded pattern with a wave-like appearance.
Gold chatons serve as bushings for the bearing jewels. This used to be important for adjusting the vertical play of the wheels and pinions, but nowadays chatons play a primarily decorative role. Screwed gold chatons are found only on very high-quality watches. One can readily imagine how long it takes to polish the chaton and the screws, to heat each screw until it acquires precisely the same blue hue as the other screws and to assemble all the parts. The balance cock of the 1815 Tourbillon has a diamond cap jewel – it’s another special feature that Lange uses only on its complicated watches.
Lange uses additional decorative techniques to ennoble the limited special editions in its Handwerkskunst line. The elaborate relief engravings on the bridges allude to the starry decor on the enamel dial. In addition, as on antique pocketwatches, the tremblage technique is used to give a grainy finish to the plate’s surface. This chronograph movement also contains a particularly large number of steel parts, e.g., springs and levers, which Lange has decorated with a linear brushed finish. Like the bridges and plates, the steel parts also are beveled (i.e., their flanks are angled to exactly 45 degrees) and manually polished because no machine can produce the precisely angular shape of the inner corners.