Location: Zurich, Switzerland
Date: December 30, 1993
Passing the first half year of my apprenticeship - lots of miscellaneous watches, clocks and other devices were repaired and taken care of. Yet another challenge was waiting for me; manufacturing and replacing components of a defective driving wheel of an old english clock.
The speciality? A helical groove needed to be milled into a barrel-drum...
I was using the only machine in Paul’s atelier which was able to perform this specific task; an old Schaublin 65 with a special device which allows to connect the headstock of the lathe with one of the two slide-blocks. When turning the spindle the horizontal slide-block moves at the same time, however, the correct transmission ratio still needed to get determined.
The barrel-drum and the barrel-axe needed to be replaced. The critical path for this work was to measure all the necessary dimensions and to prepare the lathe for milling the helical groove. The pitch needed to be equal to the original, worn piece. Several test runs were necessary prior to end up with the final and correct groove cut.
The freshly cut grooves need to get slightly polished in order to round them up. Otherwise the sharp surfaces may damage the winding cord of the clock.
Even though you think it might be impossible to manufacture specific components or to handle special processes, give yourself a try and exercise! The result is often better than initially imagined!