Despite being powered by borderline ancient spring technology, the mechanical watch ranks as one of man’s most complex machines. What appears so simple on the outside — the hour hand slowly creeping, the minute hand maintaining a steady lead, both at a virtual standstill when compared to the smoothly sweeping second hand — is infinitely more complicated on the inside. It’s no surprise that impossibly small bridges, gears, and springs are susceptible to being thrown out of whack by outside elements. While sudden shock and changes in temperature are two of the more obvious culprits, magnetic fields are a bit more subtle.
Magnetic fields have been the enemy of an accurate timepiece for as long as mechanical watches have been around. As the presence of technology increased, so did the potential for magnetized balances. All it takes to affect a watch without magnetic protection is a quick exposure to a magnetic field found in everyday items like speakers, computers, and microphones. At a minimum, weak magnetic fields can throw your watch a few seconds ahead, which is an obvious nuisance. At the worst, strong magnetic fields can wreak absolute havoc on a watch’s ability to maintain time.
If everyday electronic items can cause issues, you can imagine what the strong magnets encountered by engineers, scientists, and pilots would do. Members of these occupations wanted to wear watches too, and so early watchmakers were forced to search for answers. The exact origins of the anti-magnetic watch are difficult to track down, but many signs point to a non-magnetic, palladium-made escapement patented by Charles-Auguste Paillard in the mid 1880s. Several years after his invention, the Geneva Non-Magnetic Watch Co. began offering pocket watches with his escapement. For the next 25 years or so, variations of the Paillard escapement found their way into pocket watches from the Non-Magnetic Watch Co. of America, Peoria Watch Co, Paillard Non-Magnetic Watch Company, A.C. Smith Watch Co, A.C. Becken Co, and Elgin. Meanwhile, companies like IWC and Waltham patented their own non-magnetic designs.
While it’s not entirely clear who pioneered the first anti-magnetic wrist watch, IWC’s Mark 11, released in 1948, was certainly an early one. Rolex and Omega were not far behind with the Milgauss and Railmaster, respectively. These three watches were purpose-built tool watches that relied on a soft iron protective layer around the movement (colloquially referred to as a Faraday cage) for protection. Thanks to the foolproof Faraday cage — it’s still used today — and resilient construction, the original Mk11, Milgauss and Railmaster would all still pass muster according to modern official anti-magnetic standards (ISO 764), which require resistance to a field strength of 4,800 A/m (amperes per meter, the International Unit for magnetic field strength).
In more recent years, watchmaking materials have improved to the point where many Swiss-made mechanical watches meet minimum anti-magnetic standards. But that’s not good enough for us; we’re bringing you six of the most badass anti-magnetic watches on the market. Each has the same magnetic field resistance, 80,000 A/m, except for Omega’s offering, which…well, it puts the other timepieces’ resistances to shame. Now, go forth and fear no refrigerator magnets.
In 2007, Rolex revived the Milgauss ($8,200) line originally made for scientists working at CERN. Milgauss is no random name: the original version had anti-magnetic protection up to 1,000 gauss (that’s milli-gauss, which equals just about 80,000 A/m, if you were wondering). This time around, Rolex didn’t stop at the Faraday cage. Inside the Milgauss, you’ll find Rolex’s benchmark Parachrom hairspring, as well as other non-ferrous materials throughout the movement. Despite the likely increase in anti-magnetic capabilities, Rolex kept the name to honor its predecessor. With a trademark lightning bolt second hand, the Milgauss is nicely sized at 40mm and comes in three variations: black or white dial with a clear crystal, or the anniversary model with a black dial and green-tinted crystal.
IWC Ingenieur Automatic Mission Earth
Not long after introducing the Mk11 pilot’s watch, IWC began producing a new line of watches made for engineers known as the Ingenieur. Designed by legendary watchmaker Gerald Genta, the Ingenieur’s claim to fame was its resistance to magnets. Through the years, IWC has maintained the famous Genta design cues despite releasing dozens of different references. Up until the Omega >15,000 Gauss, several Ingy references released in the late 1980s and early 90s held the claim of being the “most anti-magnetic watches” with magnetic field resistance at 500,000 A/m (versus about 1,000,000 A/m for the Omega). Even though the Mission Earth ($8,300) reference registers at 80,000 A/m, it should have more than enough imperviousness for anyone who’s not an MRI technician. Add that to 110 meters of water resistance and an integrated shock-absorption system, and this is one highly capable timepiece.
A watch can be considered anti-magnetic if it can run within a 30 seconds per day deviation while housed inside a magnetic field of 4,800 A/m. And while that sounds like a lot, consider that even a small magnet, like those found in your iPad cover, stereo speakers or computer monitor, can be enough to throw your fine timepiece out of whack by causing the hairspring to effectively “stick” to itself. Should you find your watch suddenly running wildly slow or fast, don’t despair. A watchmaker can easily de-magnetize it in minutes, returning it to proper working order.
For reference, here are the Amperes/meter ratings of some common magnets.
35 A/m – Earth’s magnetic field at its surface
4,000 A/m – a typical refrigerator magnet
8,000 A/m – a small iron magnet
5,500,000 A/m – an MRI machine
6,600,000 A/m – CERN Hadron Collider magnet
Sinn 756 DIAPAL
Sinn is well known for producing borderline bombproof watches geared toward professional use. Their first use of anti-magnetic technology goes back to 1994 in their model 244. The 244 could resist magnetic fields up to 80,000 A/m using a faraday cage, and with its titanium case, it also reduced the magnetic signature given off by the watch itself. Just about all of Sinn’s watches meet the minimum requirements to be labeled “anti-magnetic”, but a handful use a Faraday cage and therefore reach 80,000 A/m of resistance. We recommend going all out and springing for the 756 DIAPAL ($3,580), a reference that incorporates most of Sinn’s major technological advancements with classic German over-engineering.
Bremont’s Martin-Baker (MB) series was designed along with the British aviation company of the same name. Intended to be the epitome of an aviation chronometer, the MBI and MBII ($4,950) have serious anti-magnetic and anti-shock capabilities. The handsome 43mm timepiece has somewhat hidden orange accents on its case. The faraday cage allows for 80,000 A/m of protection, and the anti-shock movement mount will survive ejection from an aircraft. In fact, the MBI is only available to pilots who have ejected out of a Martin-Baker seat. We certainly won’t judge if you’re only eligible for the MBII.
Coming up on its 20th anniversary, Damasko represents the best of German engineering. Their ice-hardened steel is almost eight times harder than titanium and is almost as hard as sapphire. With the exception of pieces containing their new in-house movements — yes, this boutique brand has in-house movements — all Damasko watches come equipped with a faraday cage. So, if you’re looking for anti-magnetic protection, we could just tell you to close your eyes and pick a model, though our choice would be the DC66 ($2,275). It features a chronograph function, day and date and a rotating bezel that could potentially be used for diving or a second timezone. Rest assured, you can test this watch with the roughest of elements and it will still age better than Sophia Loren.
Omega Aqua Terra >15,000 Gauss
At Basel 2013, Omega unveiled the very first fully non-magnetic movement, the Aqua Terra >15,000 Gauss ($6,300). There’s no Faraday cage here, folks. The Caliber 8508 is entirely made of non-ferrous materials. Notice the strange “>15,000 Gauss” in the name; Omega wanted to make sure we knew the movement can withstand magnetic fields above 15,000 gauss (or a whopping 1,200,000 or so A/m). A higher certification could have been achieved — if only Omega had testing equipment that could produce more intense magnetic fields. Looking mostly like a standard Aqua Terra, the >15,000 Gauss version has a black-and-yellow banded second hand (a curiously similar styling cue to the orange lightning bolt hand of the Milgauss). If the Aqua Terra isn’t your look, fear not: Omega plans on rolling this technology out to all of their watches by 2017.