XMThe term “finishing” encompasses the vast array of techniques performed on watch components, once they have been produced by machines. All the traces of machining are erased, parts are polished and decorated with extreme care by hand. Raw metal is turned into works of art – horological alchemy.
MIRROR POLISHING
Also called black polish (poli noir, miroir ou bloqué in French), this time-consuming finish is characteristic of Haute Horlogerie and is used to acquire a perfectly smooth surface of metal parts, which in return reflect the light like a mirror or appear black when gazed from a certain angle.
Such polishing requires a perfectly flat surface, with not a single irregularity on the part in question and light reflections must be in one single direction.
For the calibre SXH5 bridges, once machined, the bridges are polished several times in succession with increasingly fine abrasives. First with a 1-3 micrometre diamond paste on a composite/metallic polishing disc. One of the main objectives at this stage is also to make sure that the bridges are perfectly flat and within strict dimensions. The height of each piece is measured and must be in between tolerances measured in micrometers.
For the final polishing, a softer disc covered with abrasive canvas is used. The diamond paste used is 0-1 micrometre.
Finally, the pieces are washed as it is crucial that these be extremely clean, free from any residual abrasives. Each bridge is individually controlled using a binocular to make sure there are no discernable imperfections… Only after this meticulous inspection are these ready to be assembled into the movement.
Xavier de Roquemaurel
Pierre Millasson
Valeria Garavaglia