Just About Watches
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Now, I’ll say this up front. No two movements are the same. Different manufacturers, calibres, and complications bring different designs and nuances. But I want to walk you through the general anatomy of a mechanical wristwatch, not to sell you on anything, but to help you understand the moving parts and the thinking behind them. I’ll probably dive into specific movements in our online magazine down the line, but for now, think of this as a good grounding.
Let’s start from the outside and work our way in.
A watch is a whisper from time itself. A silent reminder that every fleeting second holds the weight of memory, the promise of purpose, and the beauty of now.
-Kev Green
The case is the structure that holds everything together. It protects the movement, gives the watch its shape, and determines how it wears on your wrist. It might be made of stainless steel, titanium, ceramic, carbon fibre, or precious metals. Some are coated, some brushed, some polished. The case has two main jobs regardless of material: shield the internals from shock and keep moisture, dust, and air out. That’s where case design matters. Sharp edges, crown guards, display backs—all those choices are functional first, and aesthetic second.
The crystal is the transparent cover that lets you see the dial. Acrylic crystals are cheaper and more forgiving when scratched. Mineral glass is harder but still prone to marks. Sapphire is the top-tier choice—highly scratch-resistant, often with anti-reflective coatings. Whatever it’s made from, the crystal is more than just a window; it’s a seal. If it’s not fitted correctly, moisture can get in—and that’s a short road to trouble.
Some bezels rotate, some don’t. A rotating bezel might be used to time a dive or track a second time zone. Others are fixed in place and purely structural. Either way, the bezel is often the most exposed part of the case. It’s where knocks, scrapes, and everyday wear tend to show up first. Depending on the watch, it might contain a gasket or two to help maintain water resistance.
The crown is your direct interface with the movement. You use it to set the time, wind the mainspring, and adjust the date in many watches. Crowns might screw down to help prevent water ingress, especially on divers or tool watches. Others are push-pull. But it’s what’s behind the crown that deserves attention.
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The case of a watch is its armour—protecting precision while reflecting personality.
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The crystal of a watch is its window to time—clear, strong, and always looking forward.
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The crown of a watch is a symbol of control—small in size, mighty in purpose, it puts time at your fingertips.
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The backcase: a hidden canvas where craftsmanship quietly speaks.
The stem connects the crown to the keyless works inside the movement. That stem passes through a hole in the case, sealed by tiny gaskets. Over time, those gaskets can wear, dry out, or deform. And if the stem gets a knock, even a subtle one, it can compromise that seal. The crown tube—the part of the case that the stem passes through—is also a potential weak point, especially if pressed into a case rather than machined as one piece. Pushers, used for chronographs or other functions, face the same risks. Each requires seals, springs, and precision tolerances to avoid letting in moisture during use.
Now we’re into what most people think of when they picture a watch—the face and the hands. The dial might look simple, but it’s the most exposed part of the movement’s front. It can be painted, lacquered, sunburst brushed, enamelled—you name it. Applied indices, lume plots, logos, and sub-dials are all fixed to the dial’s surface or drilled through it. The hands, meanwhile, are mounted on a stack of pinions extending through the movement. They might look flat and decorative, but they must be perfectly balanced and aligned to avoid interference. Even the tiniest bend can cause rubbing, resistance, or misalignment.
If your watch shows the date, there’s a wheel doing the heavy lifting behind the dial. The date wheel rotates once every 24 hours, typically jumping at or around midnight. A gear off the motion drives it, usually involving a finger or lever that pushes it along. If you’ve ever changed the date during the wrong time window and heard a click or felt resistance, that’s because you were forcing the system while the changeover mechanism was engaged—never a good idea.
- Don’t Overwind: Stop winding when you feel resistance to avoid damaging the watch.
- Consult the Manual: Always consult your watch’s manual for instructions on using the crown for its unique features.
- Gentle Handling: Be gentle with the crown, especially when pulling it out or screwing it in.
- Screw-Down Crowns: If you have a screw-down crown, ensure it’s tightly screwed in when not in use to maintain water resistance.
This is where many people gloss over the details, but gaskets are critical. Rubber or silicone gaskets sit in grooves around the crown, crystal, caseback, and pushers.
The Devil is in the Details
These are the barriers that keep out water, dust, and air. They compress under pressure and expand slightly with heat. Over time, they degrade—especially if exposed to soaps, saltwater, or thermal changes. A worn gasket might not look like much, but it can be the difference between a safe watch and a ruined movement.
Now we get into the mechanics. If the case is the body, the movement is the brain and the central nervous system. It’s where all the energy is stored, transferred, measured, and released in carefully controlled intervals.
You start with the mainspring. This is a tightly wound coil of metal housed in the barrel. When wound manually or via a rotor in an automatic watch, it stores potential energy. As it unwinds, it releases that energy through the gear train. The gear train is a series of wheels and pinions that reduce the mainspring’s powerful but rapid energy into something slow and manageable. These gears divide the energy into functional timing units: seconds, minutes, and hours. At the far end of the train is the escapement.
The escapement is a clever system—usually made up of an escape wheel and a pallet fork—that controls how much energy is released. It delivers this energy to the balance wheel, like a heartbeat, one pulse at a time. The balance wheel is mounted on a hairspring, which acts like a torsion spring. It oscillates back and forth steadily, governing the release of power through the escapement. This is what keeps time. The consistency of those oscillations is what gives a mechanical watch its accuracy.
And every pivot point in that movement—every wheel, lever, and spring—sits in a jewel bearing. Watch jewels aren’t decorative. They’re functional. Usually made of synthetic ruby or sapphire, these tiny bearings reduce friction and wear. The harder the surface, the less it deforms under pressure, and the more precise the movement remains over time. Jewels sit in the mainplate and bridges and hold the ends of arbours or pivots in place. You’ll hear of 17-jewel movements, 21-jewel movements, or higher still—each jewel representing a critical friction point in the system. More doesn’t always mean better, but they serve a real purpose.
Balance wheels are vulnerable. They swing rapidly and sit on the most delicate pivot in the movement. Shock protection systems like Incabloc or KIF use a spring-mounted jewel setting that allows a little movement on impact. It’s not bulletproof, but it can save a movement from being completely thrown out of regulation after a knock.
One thing many people overlook is how small an opening water needs. With steam or water vapour, capillary action can draw moisture along a metal stem, even if everything seems dry outside. Once inside, that vapour condenses on cooler surfaces—like the crystal or plates—and it doesn’t take much to begin the oxidation process. The oils used in a movement can emulsify. Steel parts corrode. Rust on a screw head or pivot arbor can wreck the whole system quietly, over time.
Automatic watches use a rotor—a semi-circular weight that moves with wrist motion—to wind the mainspring. This rotor spins on a bearing and interacts with a reversing gear system to wind regardless of direction. Some systems are bi-directional, some aren’t. But all of them add complexity and friction. That’s why some people still prefer manual movements—less to go wrong.
Finally, we come to the caseback. It might be screw-down, snap-fit, or secured with screws. Some have sapphire windows to show off the movement. Some are solid and thick for added protection. The caseback also houses a gasket; the watch is compromised if it’s removed for a battery change or service and not refitted correctly.
So there you have it. That’s a broad—but—detailed look at the anatomy of a watch. Not every piece has every feature I’ve mentioned. Some movements are simpler, some far more complex. But next time you put a watch on, it might help to know that you’re carrying around a marvel of engineering that deserves more respect than just being set and forgotten. And if you’ve ever wondered why a little bit of fogging inside the crystal is more than just cosmetic, now you know—it’s not just the glass or the case, it’s everything inside that’s quietly at stake.
