Watch Word this Week: Hairspring

Here’s a surefire way for a watch manufacture to impress a watch journalist: Produce its own hairsprings (also known as balance springs), which are a challenging exercise in precision to make, with tolerances of microns. This is a claim that can only be made by a handful of manufactures, including Rolex and A. Lange & Sohne. Most of the hairsprings used by Swiss watchmakers are made by Nivarox-FAR, a company owned by the Swatch Group.

A crucial component of the heart of a watch movement, the hairspring is a tightly coiled spring attached to a balance wheel – the wheel that you can often see moving back and forth through a display caseback. This balance helps to regulate the impulses from the escapement and maintain the accuracy of your timepiece.

In the name of greater precision, watchmakers such as H. Moser, Laurent Ferrier and Audemars Piguet have created single balance wheels fitted with dual hairsprings. The idea is that these hairsprings, arranged such that they mirror each other, will cancel out each other’s errors. This year, however, Audemars Piguet takes this concept a step further by launching the world’s first dual balance wheel system in the Royal Oak Double Balance Wheel Openworked.

The larger oscillating mass – comprising the two connected balance wheels – of the automatic Calibre 3132 is supposed to provide greater precision-enhancing stability. According to Audemars Piguet, this structure ostensibly translates to a decidedly un-shabby 30% gain in accuracy. And as its name suggests, the 41mm watch, available in pink gold or steel, features elaborate skeletonisation. How better to show off this striking new mechanism?