From our sister site, WatchTime Middle East, a look at how watchmaking has countered the threat of magnetism over the years, from the use of metals like palladium in 1915 to silicon in 2015.
Magnetism has been the arch enemy of mechanical timekeeping over the years. Professor Moriarty is to Sherlock Holmes to a mechanical watch. Although the watch industry has responded to this threat with many innovations over the years, readers and budding watch enthusiasts have always asked us this question: How real is the threat of magnetic fields in our world? everyday life ?
Before we answer these questions, let’s take a look at what happens to a mechanical watch when exposed to a magnetic field. The simple truth is that some parts of the escapement, like the balance and hairspring, become magnetized during such exposure. For example, the concentric circles of the hairspring can group together, thus causing friction. This could ultimately affect the amplitude and precision of the escapement. In most cases, after the magnetic field is removed, the watch can start working normally again, but in the case of a particularly strong magnetic field, it can stop working completely.
In 1915, Vacheron Constantin created an anti-magnetic pocket watch and in 1930, Tissot produced its first non-magnetic watches. In both cases, palladium was used in the construction of the escapement.
During World II, the German Air Force (Luftwaffe) received aviator’s watches whose movements were enclosed in a soft iron casing, known as the Faraday cage, to resist the effects of magnetism to high altitude. Longines supplied the Czech Air Force in the 1930s with watches with “anti-magnetic” markings on the dial.
In 1949 Jaeger-LeCoultre and IWC produced the Mk11 pilot’s watch for British RAF pilots. These watches were made under the strictest conditions set by the Ministry of Defense and required the movement to be enclosed in a soft iron case. IWC produced the Mk11 from 1949 to the early 1980s.
The 1950s were “the era of the tool watch”, in which a handful of watches celebrated the spirit of adventure and exploration of man. These include the Universal Geneva Polerouter (initially called Polarouter) designed for pilots and crew of SAS (Scandinavian Air Services) Airlines flights, which have flown over the North Pole with the aim of reducing flight times between Europe and New America.
These watches, which had to withstand the strong magnetic fields present around the North Pole, were initially delivered only to the SAS crew and were designed by a young Gerald Genta, who would design classics like the Audemars Piguet Royal. Oak and the Patek Philippe Nautilus.
Universal Polerouteur Geneva
In 1955, IWC launched the Ingenieur (Ref: 666A), the brand’s first anti-magnetic automatic watch. The work of IWC technical director Albert Pellaton, the watch was supposed to be the automatic civilian version of the famous Mk11.
He was also famous for presenting the first bidirectional rotor in an automatic movement. The first advertisements of Ingenier (“Engineer” in French) asserted that the watch could withstand a magnetism of up to 1000 Oersted (1000 Gauss). This was at a time when most mechanical watches could withstand magnetic fields of up to 100 Gauss only.
The ISO 764 standard states that, to be considered antimagnetic, a watch must withstand a magnetic field of 4,800 A / m (60 Gauss) and its accuracy must remain within +/- 30 seconds per day.
In 1956, Rolex introduced the Milgauss (Ref: 6541), a watch capable of withstanding a magnetix flux density of 1000 Gauss and was supplied to CERN scientists and power plant technicians. The Milgauss was to become the most famous antimagnetic watch of our time.
Omega launched the Railmaster (ref CK2914), capable of withstanding magnetic fields, and produced these watches until 1963 before their discontinuation. Omega revived the Railmaster a few years ago, but these are the first models that are collectable now.
In 1958, Jaeger-LeCoultre presented the Geophysic chronometer to commemorate the International Geophysical Year. Geophysics was created for engineers and scientists and was able to withstand magnetic fields from the North Pole. (More details here.)
Patek Philippe also came to the tool watch festival in 1958, with its first antimagnetic wristwatch, the Amagnetic (Ref. 3417 in stainless steel). It was produced for two years and featured a soft iron cage and, in some cases, beryllium components to additionally counteract magnetism.
Most modern watches use non-ferrous metals in the escapement, so unless they are subjected to very high magnetic fields, they should be able to withstand all of the magnetic fields they encounter on a daily basis.
In 1989, IWC introduced a rare iteration (Ref. 3508) which was tested to withstand magnetic fields up to a force of 500,000 A / m (6,250 Gauss), the most antimagnetic watch of its time.
Ulysee Nardin took a leap forward in 2001 with the launch of the Freak, the first production wristwatch to use a silicon escape wheel, it was the first time that silicon parts were used in a wristwatch. . Designed by Ludwig Oechslin, the Freak announced the use of silicon in watch movements.
This Breguet watch uses magnetic pivots in its movement. With the introduction of silicon in the moving parts of a watch movement, the battle against magnetism received a big boost, and in 2013 Omega took a new step by introducing the Master Co-Axial movement (Caliber 8508) capable of withstanding 15,000 Gauss. This is a far cry from the days when watches resisted 1,000 Gauss in the late 1950s.
The use of silicon and anti-magnetic materials in the movement ensured that the movement did not need a soft iron cage, so watches could benefit from a transparent sapphire crystal caseback. Omega hopes to deploy this technology on all of its movements by 2020.
In 2017, Zenith unveiled the Defy Lab, which used a new oscillator to replace the traditional sprung balance first used in 1657 by Christiaan Huygens. The result is an incredibly precise mechanical watch (to within 0.3 seconds). The movement is insensitive to temperature gradients, gravity and magnetic fields, so many scarecrows in current balance-spring assemblies which are subject to deformation and / or expansion, thus leading to a decrease in precision.
A version of this article appeared on our sister site, WatchTime Middle East.