Bovet's hairsprings – a secret process

Bovet is one of the very few watchmakers that actually manufacture hairsprings. How does Bovet turn the raw metal into an actual spring, thinner than hair ? A hairspring is a very thin, flat spring (except the very rare case of cylindrical springs, which Bovet masters). What leads to that specific shape is unbelievably complex, and Bovet fully masters it all. It starts with a block of metal, an alloy that is exclusive to Bovet. It is turned into a wire, then reduced to the proper diameter, then flattened. Dozens of times. The end result is 0.03 mm thick thread. That's thinner than hair (hence its English name). At that stage, the wire is soft and dull. Bovet's skilled and secretive staff rolls it up and then comes the actual magic. The hairspring is put in an oven. Duration? Temperatures? Pressure ? There's no knowing. That is one of the best-kept trade secrets of Bovet. One thing is for sure : once it comes out of that oven, the hairspring has become awesome. Find out why in our next post.