Since the first watch escapements were invented, watchmakers have been battling one invisible yet powerful enemy: magnetism. It’s a silent force that can drastically affect the accuracy of a mechanical watch, throwing off timekeeping without warning. One moment your watch may be ticking away perfectly, and within minutes, it could be 20 minutes off, leaving you confused and frustrated.
In this post, we’ll explore the impact of magnetism on mechanical wristwatches, why it happens, and how you can protect your timepiece against it.
Why Magnetism Is a Watchmaker's Foe
There are only a handful of external forces that can influence a mechanical watch's performance, and magnetism is one of the most significant. Magnetism affects the metal parts inside the watch, especially sensitive components like the hairspring. When exposed to a magnetic field, these components can lose their precise movements, causing your watch to lose or gain time dramatically.
Most minor magnetic fields only cause temporary disruptions in your watch’s accuracy. For example, if your watch comes near a magnetic field, such as a speaker or a fridge magnet, the hairspring may experience slight pull or push forces, causing your watch to run fast or slow. Once you move away from the source of magnetism, the timekeeping accuracy typically returns to normal.
The Bigger Problem: Permanent Magnetization
However, magnetism becomes a more serious issue if parts inside the watch actually become magnetized. If a watch is exposed to a strong enough magnetic field—such as those found in airport security equipment or MRI machines—the steel screws, pinions, and even the hairspring inside your watch can turn into magnets themselves. When this happens, the watch’s components will continuously interact in ways they weren’t designed to, leading to severe and lasting timing errors.
Imagine traveling through airport security, where metal detectors and X-ray machines use powerful magnets. You may find that after clearing security, your watch is suddenly hours off, and the time just won’t correct itself. This is likely because parts of the watch have been permanently magnetized.
How Watchmakers Fix Magnetized Watches
Fortunately, this problem can be reversed with a process known as demagnetization. The structure of magnetized materials can be realigned so that they no longer function as magnets. In every watchmaker’s workshop, you’ll find a device called a demagnetizer, which reorganizes the electrons in the metal components to restore them to a non-magnetic state.
At my workbench, I often use a rare earth magnet to demonstrate how metal parts can be magnetized or demagnetized. By simply dragging the magnet along a screwdriver blade, I can create a new magnet. This blade can then pick up steel screws with ease. However, in watchmaking, we want to avoid this kind of magnetism. If I were to magnetize every screw, it would cause interference with the delicate inner workings of the movement, throwing off the time.
That’s why, before assembling any mechanical movement, I demagnetize all the parts. I’ll even demagnetize them again once the movement is fully assembled, ensuring that any remaining traces of magnetism are removed.
Signs Your Watch May Be Magnetized
When a watch becomes magnetized, it often shows up as an amplitude deviation. The balance wheel, which controls the timekeeping, may not be swinging as far as it should. Think of it like a clock pendulum that only swings a little bit instead of its full range. As a result, you’ll notice large timing errors, and in extreme cases, the hairspring may stick to itself, causing the watch to stop running altogether.
But rest assured, these issues are usually temporary and can be fixed with a quick visit to the demagnetizer. You may have picked up this unwanted magnetism by going through airport security, being near MRI machines, or even standing next to certain industrial equipment.
How the Industry Is Fighting Magnetism
Watchmakers and designers are constantly developing new ways to combat magnetism. One solution is the use of a magnetic shield placed underneath the watch case back. This shield helps block magnetic fields from reaching the delicate movement inside. However, powerful magnets, like those found in scientific research equipment, can still penetrate this barrier.
The more advanced solution is the use of silicon. Silicon components, such as a silicon hairspring, are completely unaffected by magnetism. This high-tech material has become the most effective way to prevent magnetization in modern watches. By replacing traditional metal parts with silicon, watchmakers can essentially render a watch immune to magnetic fields.
The Debate: Silicon vs. Traditional Metal Hairsprings
While silicon offers excellent protection against magnetism, it's not without its drawbacks. Silicon parts are manufactured using silicon wafers and specialized equipment, which means a watchmaker cannot manipulate or repair them once they’ve been made. If a problem occurs during the manufacturing process, the silicon part must be discarded and replaced with a new one.
On the other hand, traditional white alloy or steel hairsprings have stood the test of time in the watchmaking world. These materials allow a watchmaker to repair or modify parts by hand. If a steel hairspring is damaged, we can fix it, ensuring the longevity of the timepiece. However, the downside is that these metal parts are susceptible to magnetism.
As a watch collector, you may find value in both options. Silicon provides cutting-edge reliability, while traditional metal offers a connection to the craft of watchmaking. For collectors who appreciate traditional craftsmanship, investing in a demagnetizer may be the perfect solution. It allows you to enjoy the benefits of a classic steel hairspring without the downsides of magnetism.
Taking Control: Be Your Own Watchmaker
There are very few things you can easily fix at home when it comes to a mechanical watch, but magnetism is one of them. For a relatively low cost, you can purchase a demagnetizer and timing tools to keep your watches in check. As a watch enthusiast, learning to demagnetize and regulate your timepiece is a great way to gain a deeper understanding of its mechanics and maintain its accuracy.
By taking a more hands-on approach, you not only protect your watch from the effects of magnetism but also become more connected to the art of watchmaking itself.
