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Anti-Aging for the Skeleton

It wouldn’t have lasted much longer: the yellow skeleton clock from our museum was in need of a thorough restoration.

Where else but at Beyer are apprentices allowed to get their hands on a valuable museum clock (under expert supervision, of course)? From the ground up and with all the time they need? This was Sophie Krienbühl’s privilege: the skeletonised movement from the period just before the French Revolution was in danger of running out of breath. Instead of ten days, the energy reserves, freshly wound, were only just about enough for one. The approximately 300 teeth and flanks of the centre wheel were so worn out that the winding forces were affecting other parts and bending little gears. The movement was on the verge of jamming. It had to be practically rebuilt from scratch.

 

The restored skeleton clock is back in the clock museum.

This would have been much easier if normal brass could have been used for the new components: its lead content makes it relatively easy to work with. “But that would not have been in keeping with the idea of originality,” says Sophie Krienbühl: “At Beyer, when we restore something, we always do it with the original condition in mind.” So lead-free brass was chosen, and that is tough and stubborn. The advantage, though, is that its colour changes evenly over the decades and takes on the “right” patina.

Back to the original

In an external workshop under the supervision of a retired pro, Sophie Krienbühl was allowed to file, bend, pinch, mill the gear teeth on a huge lathe on the newly manufactured centre wheel and take the many steps necessary restore the mainspring barrel to its original condition (it was a veritable patchwork of repairs performed by watchmakers over the centuries). This required the manufacture of a new barrel drum and barrel core. Also, English imperial (inch) screws and threads were created for all attachments. “When we finally wound the skeleton clock, I was super nervous,” the watchmaker laughs. “And when, six days later, the balance wheel was still oscillating beautifully evenly, I knew: that’s it! After all the suspense, it was a feeling of tremendous relief.”

«Ich gehe heute anders ins Museum»

Wie reagierten Sie, als Ihr Chef Sie mit dieser Aufgabe betraute?
Man nimmt im ersten Lehrjahr zwar Grossuhren durch, aber man übt natürlich nicht an kostbaren antiken Stücken. Ich zappelte hin und her zwischen totaler Euphorie und riesigem Respekt. Und eigentlich blieb das bis zum Schluss so.

Was war der schwierigste Moment?
Es gab eigentlich keine schwierigen Momente: René Rietmann, der auf mich – und wohl vor allem auf die Skelettuhr – aufpasste, führte mich enorm kompetent und rücksichtsvoll durch den Prozess. Jeder Schritt war ein Genuss.

Worüber staunten Sie am meisten?
Über die Dimensionen der Werkzeuge und Werkbänke, um die doch sehr grossen Teile nachzubauen. Und über die Kraft, mit der man bei dieser Arbeit ans Werk gehen muss.

Hat es Sie gepackt – sehen Sie Ihre Zukunft bei den Grossuhren?
Es war toll, doch ich tendiere eher zum Kleinen, Feinen, Pingeligen. Aber ich gehe heute anders ins Museum, wo «meine» Skelettuhr thront. Irgendwie mit gestreckterem Rücken.

Sophie Krienbühl, third-year apprentice

Text: Matthias Mächler

 

Beyer Chronometrie