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  • Writer's pictureMarc Jenni

8-Day movement - Part I

Updated: Feb 9

Location: Zurich, Switzerland

Date: March 8, 1996

I would have never guessed that the caliber 12 will one day become the power engine of Paul Gerber’s Tourbillon desk clock. Well, back in the old days, the very first 8-Day desk clock movement served - again - for a fancy jeweled timepiece.

The 3 top bridges were finished with «Côtes de Genève» and the main plate with a «Perlage». In order to reach 8 days of power reserve, the mechanism features 2 barrels and an 8-day wheel. 

The balance-cock needed to be prepared for drilling the hole in order to fix the balance-spring stud or hairspring-stud. Afterwards a thread of M0.6 was cut in the pre-drilled hole of 0.5 mm.

The index is fitted friction tight on the upper end-piece. In order to add the separation to the closed index body, here’s how I proceeded: After hardening the indexes I fixed them between the jaws of a bench-vise and hit them with a special punch. The punch needs to have a stop the way the index body does not get jammed or bent during the exercise.

In the 2nd part I will show further pictures of the finished movement as well as some detailed pictures of the top balance-end-pieces and indexes...


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