Magnetism was, through most of the history of watchmaking, a significant problem. The issue was at the very heart of the watch itself. There are two coiled springs inside a watch –one, the mainspring, provides power. The other, far more delicate, is the spiral balance spring, so thin that it’s also called the hairspring. Its inner coil is attached to the axis of the balance wheel, and its outer end is fixed to the plate of the watch; it’s what determines how fast, and how regularly, the balance swings back and forth (in other words, how fast it ticks.)
As its properties are what determine how accurate a watch is, it’s important to make it in such a way that it’s influenced by external factors as little as possible, and that’s where the problem of magnetism comes in. For most of the history of watchmaking, the balance spring was made of plain steel, generally tempered to a deep blue. Steel, of course, is easily magnetized, and if the coils of the spring begin to attract each other magnetically, the effect on accuracy is disastrous. Modern balance springs are made of alloys that resist magnetism better than steel, but a strong magnetic field can still disrupt their abilities to keep time, and one of the facts of modern life is that strong magnetic fields are more and more ubiquitous –in everything from electronic devices and stereo speakers to the magnetic clasps of purses, cell phone, and tablet computer cases.
Anti-magnetic watches, therefore, have been for decades and still are an object of active research. There are basically two approaches –you can either surround the watch movement with an anti-magnetic shield (the material of choice is usually soft iron, which provides a pathway for magnetic fields that passes around the movement rather than through it) or you can make the most important parts of the watch from materials that are not affected by magnetism. Specially made anti-magnetic watches have a small but loyal collector following, and some of the most important vintage and modern models specifically designed to be highly resistant to magnetic fields are the Rolex Milgauss, the Omega Railmaster, and the IWC Ingenieur.
The record for resistance to magnetic fields was until recently held by IWC, which made a very small number of Ingenieur watches from 1989 to 1993 known simply as the IWC “Ingenieur 500,000 A/m.” (“A/m” stands for “amperes per meter,” a unit of measurement for magnetic field strength.) Recently, however, Omega announced that it has developed a movement with an astonishing resistance of 1.2 million A/m. The prototype movement has been shown in an Omega Seamaster Aqua Terra, with the dial reading “Co-Axial Chronometer, >15,000 Gauss” and a black and yellow seconds hand.
Omega has announced it will be officially debuting the watch at Basel, for the annual BaselWorld watch and jewelry trade show. The IWC Ingenieuer 500,000 A/m was reportedly successfully tested to 3.9 million A/m, in 1989, but IWC chose to officially rate it at 500,000 A/m, so the Omega watch will become, once it’s announced, the record holder for a series produced watch with the highest official anti-magnetic rating. To put it in perspective, for a watch to be called anti-magnetic, it need only be resistant to 4,800 A/m. Once Omega’s released the watch, it will be –and should be for some time –the new world champion (and a new magnet, as it were, for collectors.)
Final pricing and availability to be announced by Omega at BaselWorld 2013 in April.