Time to do some more work on the WOSTEP WO1 watch. We’ve made the winding stem and balance staff, now we need to work on the bridges.
The bridges are supplied machine-finished which means they’ll work fine but don’t look great. It’s hand-finishing which separates the mediocre and the functional from the great and the beautiful.
The first step is to flatten the upper and lower surfaces on paper. This improves the appearance by leaving a grained finish but (more importantly) ensures the surface is flat. The aesthetics can be further improved later but you need to start work with a level playing field.
Next is flattening the sides. Trickier as it’s vital to retain the sharp corners to give the best appearance. For this we use a piece of brass bar, faced off at each end in the lathe so as to ensure the ends are flat and at 90 degrees to the sides. Placing the work piece on the bench, you can then wrap paper around the brass and carefully work the flanks to the same grained finish as the upper and lower surfaces.
Once the sides and uppers are free from machine marks, the next step is to polish the countersinks in the screw holes and jewel holes. A circular cutter is used to give a consistent finish and then a piece of peg wood is shaped so that it matches the shape of the countersinks. The peg wood is then mounted in the lathe and diamond polishing paste applied. After that, you just push the peg wood into the countersinks and – voila – a polished finish.
Finger cots stop you touching the work piece with your skin. Grease and acid on the surface of the skin will tarnish German silver in hours. A finger print can permanently etch itself into the metal if left!