Timepiece Chronicle

In-depth, passionate and entertaining articles that explore the stories behind great watches

Steel Attraction: The search for Anti-Magnetic Watches

Steel Attraction: The search for Anti-Magnetic Watches

The Omega Aqua Terra >15,000 Gauss. Image courtesy of Omega. 

The Omega Aqua Terra >15,000 Gauss. Image courtesy of Omega. 

Electromagnetism is one of the four fundamental forces that has kept the universe together since the dawn of time yet it has only been in the last sixty years that it has been been a problem for watchmakers. Key parts of the parts such as the balance spring, balance wheel and escapement are small enough that even light magnetic fields can exert influence on them cause inaccuracy or even stoppage. The oscillation of a balance spring can be affected by magnetism causing an uneven frequency which affects the accuracy of a watch. If the watch retains even a small amount of magnetism it can cause long term problems even after the field is no longer present.

The potential havoc magnetism could cause was first realized in 1825 by Jacques-Frederique Horiet who addressed the Society of Arts in Le Locle about how the magnetic pole affected the on-board Marine Chronometers during a polar expedition in 1820. Development of an anti-magnetic movement started in 1846 with Vacheron Constantin but progress was exceptionally slow and it would take decades for a working piece to be made. These early attempts focused on utilizing materials that were not able to be influenced by magnetism. Breguet experimented with glass balance springs and other watchmakers tried gold however these all proved too delicate and couldn't be made on a large scale whilst maintaining the precise specifications needed to be accurate. 

Charles-Auguste Paillard would make the first big step when he made a balance spring made of a palladium alloy. As is so often the case with scientific accomplishments Paillard initially set out to create a hairspring resistant to excessive heat however palladium proved very effective in combating magnetism. He succeeded in 1877 and by 1887 22 out of 23 watches in the French Annual Timing Trials had palladium balance springs. In 1888 IWC utilized Paillard's patents to create two anti-magnetic movements with balances, balance springs, escape wheels and pallet levers all made from palladium with a park fork in bronze and arms in gold. These non-ferrous materials all had low iron contents which made them very resistant to magnetism.  

After sixty years of experiments Vacheron Constantin made the world's first anti-magnetic pocket watch chronometer in 1915. In 1930 Tissot would be credited as creating the first serialized anti-magnetic wristwatch imaginatively called the Antimagnetique. Similar to the early attempts by IWC and Vacheron Constantin, the Antimagnetique used the non-ferrous material palladium to resist the influence of magnetism on the escapement. 

Today the requirements for an anti-magnetic watch are listed under ISO 764 which states that a watch "must resist exposition to a direct magnetic field of 4,800 A/M and must keep it's accuracy to within +/- 30 seconds a day as measured before the test". From researching this article I can attest that the complexities of magnetic fields crescendos very rapidly so for the purposes of this article all you'll need to know is this simplified version: Magnetic fields are measured in A/M, amperes per meter. Gauss (G) and Tesla (T) are units of measurement that also measure magnetic fields. Tesla is part of the modern International System of Units however it's base measurement is high so the older Gauss measurement is still used to measure smaller fields (0.1 Tesla is equivalent to 1000 Gauss) The Earth's magnetic field is 0.25 Gauss, a fridge magnet is 50 and an MRI has between 600 to 70,000. I'm so sorry for all your physicists reading this pulling your hair at my oversimplification.

As technology and electronics became more commonplace in the middle of the twentieth century, the need for professionals to wear and anti-magnetic watch increased. In the 1940's Great Britain's Royal Air Force requested a watch that could resist the large magnetic fields produced by the giant radial engines of the Spitfires and the Hurricane. Rather than use non-ferrous materials, IWC placed the movement of their Mark XI pilot's watch inside a magnetic shielding case. This case is known as a Faraday Cage and is named after the British scientist Michael Faraday who invented it in 1836. A Faraday cage does not negate or cancel magnetic fields but rather provides a 'pathway' that guides the fields away from the movement inside. (Again physicists, I'm so sorry).

The scientists at CERN in Switzerland were regularly being exposed to magnetic fields ten times the strength that most watches could take so in 1954 requested Rolex to make a watch that could withstand these extreme levels. Taking it's name from the French for 1000 Gauss (Mill Gauss), the Rolex Ref. 6541 Milgauss was the first watch to be resistant to such high levels. The movement was placed in a Faraday cage with a dial of two interconnecting aluminum layers placed on top to further shield the way. Whilst the modern Milgauss Ref. 116400 has a case, dial design and bezel more similar to the later Ref.1019, it still shares the eye-catching lightning bolt second hand from the original. 

One year later IWC created their anti-magnetic watch, the Inginieur Ref.666. The two models that entered production, Ref. 666A (Without date) and Ref. 666AD (With date) would remain unchanged for over twelve years. Like the Milgauss the Ref. 666 was intended for professional use by engineers, technicians and pilots with the logo reminiscent of the international voltage symbol. Eventually in 1976 Gerald Genta, designer of the Royal Oak and Nautilus, designed the Ref. 1832 that combines the use of non-ferrous materials and a Faraday cage. The world was not ready for another Genta tribute to the Octagon and only 550 were sold worldwide.  

In 1957 Omega followed suit with the Railmaster CK2914, another watch with a Faraday cage protecting the movement however this was only resistant to 900 Gauss. In 2009 Hodinkee found a Railmaster commissioned for the Pakistani Air Force had been changed to read Seamaster instead. One commenter whose father-in-law served as an Air Force Wing Commander in Pakistan said that a negative association with railways, the British Raj and the lower classes could have prompted the Air Force to change the name to a more dignified one. During the seventies and eighties the progress of anti-magnetic movements slowed as more attention was placed by Swiss watch industry to survive the quartz crisis. In 1989 IWC created the Ref. 3508 which was able to withstand magnetic fields of up to 6250 Gauss, the highest to date, with a balance spring made of the same alloy that the Rolex Parachrom Blu balance spring is made from today. 

What might not instantly apparent is that the majority of anti-magnetic watches have no date windows or complications. In order for a Faraday cage to fully protect the movement from magnetic fields it must be as complete as possible with even a hole as small as a date aperture making the movement more vulnerable. At the beginning of the 21st Century Omega and Patek Philippe had been experimenting the use of silicon balance springs resulting in Patek's Spiromax, Role and Omega's SI14. Rolex has taken a slightly alternative route with the use of the Parachrom alloy hairspring across the majority of models and the Syloxi hairspring in Pearlmaster and the 36mm Yachtmaster. It was in 2013 with the release of Omega's Seamaster Aqua Terra >15,000 Gauss and the Caliber 8508, a movement that Omega claims to be the world's first truly anti-magnetic mechanical watch movement. With a balance spring made of silicon with staffs and pinions in the escapement made from NivaGauss there was no need for a Faraday cage so the >15,000 has a date window at 3 o'clock as well as a sapphire crystal case-back. At the time Stephen Urquhart said that by 2017 he wanted all Omegas with a Co-Axial caliber to be equally resistant to magnetism. With the introduction of Master Co-Axial and more recently the Master Chronometer and METAS certification standards, Mr. Urquhart seems on track for his ambitious goal. 

Much of the development of anti-magnetic watches has been focused for specialist needs so it is worth asking whether an everyday consumer needs to worry about their watches. Omega's video advertising the Master Co-Axial Calibers compares the threat of magnetism at home to a serial killer lurking ominously in every speaker, purse clasp and laptop. The levels to which Omega's Master Chronometer movements are resistant to magnetism is overkill however as the blanket of technology covers us more and more the need for some base level of protection is appreciated. For the time being it is only the luxury watch bracket that is concerned about the perils of magnetic influence with a few outliers from Ball and Sinn providing a few pieces at a more approachable price. It is unlikely that magnetism is a pressing concern for the cheaper brands as any influence magnetism could have will not be greater than the variance a non-chronometer rated watch has on a daily basis.

Like having a dive watch water resistant to 600m, a depth that will crush a human with ease, the extreme levels of magnetic resistant that some watches have is a satisfying reminder that the Swiss watch industry is ready to protect their creations against any foe, no matter how rare in everyday life.

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