SJX Watches
Insight: Hairspring Materials and Evolution Part II
Part I of our story on the evolution of hairspring materials covered temperature compensation along with the development of the first specialised balance spring alloy, Elinvar. The story brought us to the 1920s, when scientist and horologist Charles-Edouard Guillaume (1861-1938) finished his work on nickel-iron alloys and watchmakers begun embracing Elinvar springs paired with mono-metallic balances. In this second part we turn to newer hairspring alloys, like the now-ubiquitous Nivarox. Then we look at today’s landscape and the future, touching on research done by the Swatch Group with alternative, niobium-based alloys and also the specialised but obscure Seiko SPRON 610 hairspring. Lastly we discuss silicon springs, which are growing more prevalent across a range of timepieces. Elinvar’s weaknesses Elinvar was by far the greatest breakthrough in self-compensating alloy hairsprings at the time. Guillaume considered Elinvar good enough and not needing further improvement - unsurprisingly since he was its inventor - but other watchmakers and engineers continued to experiment with iron-nickel compounds because Elinvar’s inherent properties made it a good, but imperfect, material. Even though the alloy behaved predictably with temperature changes, its physical properties were not ideal to begin with. Elinvar was a soft metal, which posed its own suite of problems for spring applications. The importance of softness in terms of hairspring performance is not related ...
