Unique: 3/4 Plywood By Ferdinando Adolf Lange

February 18, 2015 is the 200th anniversary of Ferdinand Adolph Lange’s birthday. The Dresden watchmaker introduced 3 to the precision watchmaking industry. / 4 splint. The emergence of this component stems from his insistence on building precise and reliable timepieces, and the 3/4 splint quickly became an important element of his pocket watches, unique in style and quality. To this day, most A. Lange & Söhne movements are still equipped with this component. In fact, this eye-catching component has been an important mark for Lange for more than 140 years.

Three Lange models with 3/4 splints: (from left) Richard Lange Tourbillon ‘pour le mérite’, Richard Lange and 1815 UP / DOWN
   After Ferdinando Adolf Lange established the watch factory on December 7, 1845, he was committed to improving the design of the movement in a systematic way. At that time, there was a technical problem with the pocket watch movement that annoyed him: in general, all bearings and gears were arranged under separate bridges and bridges. During the assembly process, the watchmaker needs to handle each component carefully and correctly fix the gear in the corresponding position. They must be tireless and make trial and error. Because as long as the position of one of the splints is adjusted, the other splints must be rechecked, and re-positioned if necessary. In addition, after a period of time, the splint will move slightly, so that the pocket watch needs to be readjusted from time to time.
Ferdinand Adolph Lange

   Ferdinando Adolf Lange cannot accept this situation. His goal was to create timepieces of exactly the same quality. Therefore, he developed an upper splint that could accommodate all important gear bearings. This allows the individual bearing positions to be individually fixed. Although watchmakers need to use specific skills to ‘guide’ all mandrels into the drill holes under the splint at the same time, this new method will undoubtedly make the assembly process smoother. It took Lange nearly 20 years to continuously improve the design of this splint. After different processes, by 1864, the area covered by this plywood movement increased to three-quarters. Only the oscillation system and its balance plate are still exposed. The independent escapement wheel splint was later integrated into the upper splint. This became the final form of the 3/4 splint.
Modern 3/4 plywood made of untreated German silver, assembled in the L121.1 hand-finished movement of LANGE 1

   In March 1875, Ferdinando Adolf Lange’s design was patented in the United States. Watches equipped with 3/4 splints need to be completely disassembled to remove the barrel. Seeing this, Lange came up with a completely new method. He modified the design of the barrel, and now simply removes the barrel by loosening the two screws under the ratchet.