Assembling the Tourbograph Perpetual “Pour le Mérite”

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Presenting the making of the Tourbograph Perpetual “Pour le Mérite” by A. Lange & Söhne. The fifth watch to host the “Pour le Mérite” title, it unites five complications and is the result of a 684 part manufacture calibre. Discover the making below.

28 Jul 2017

Gurvisha Ahuja

The Tourbograph Perpetual “Pour le Mérite” is crafted in many meticulously executed steps.

Once the watchmaker has wrapped the delicate chain around the previously assembled mainspring barrel, they can integrate both components into the basic movement. The chain is then attached to the fusée. The planetary gearing or differential must be mounted first.

Using the ratchet wheel placed on the square barrel arbor, the watchmaker can adjust the final basic tension of the mainspring.

The tourbillon bridge firmly secures the cage to the chronograph bridge as it rotates suspended between two diamond endstones.

$The chronograph and rattrapante mechanism is located on the movement side. It consists of a total of 136 parts. During the assembly phase, all of the individual parts of the elaborate column-wheel ensemble are manually tweaked and adjusted. This is because the wheels, levers, arbors and springs involved in the complex switching sequences must interact in a precisely defined order within fractions of a second to prevent mechanical conflicts.$

The rattrapante hand arbor is about one centimetre long and extends from the dial to the rattrapante wheel on the opposite side of the movement. The arbor is turned from one piece of round hardened steel and painstakingly trued by hand. Then, it is passed through the hollow chronograph hand arbor.