With a mechanical watch, the parts inside are always moving and interacting with each other. However, there are only a few occasions where you, as the wearer of the watch, get to interact directly with the movement components. With an automatic watch, wearing it will keep it wound by moving your arm, causing the oscillating weight to wind the watch. Aside from that, the only direct interaction is through the crown, which is how we wind and set a watch.

For a mechanical, manually wound watch, you have to turn the crown to wind up the mainspring, which powers the watch. The crown is directly attached to a movement part, allowing you to control the movement within the watch case. With an automatic watch, you won't necessarily be winding it all the time, but you will need to adjust the time, set the date, or set other functions, all done through the crown.

Let’s take a closer look at what happens when you pull the crown out or when you turn it to wind the watch.

The Crown and Its Positions

The crown is the small knob on the exterior of the watch that you can grab to wind or set the time. When it's in position zero, it's all the way in toward the case, often providing a water-resistant seal. This is where you wind the watch by turning the crown clockwise, which transfers power to the mainspring inside the barrel. Turning the crown counterclockwise won't do anything; you'll just hear a clicking noise as a clutch releases.

When you pull the crown out to the first position, you’ll hear a click, which engages the setting mechanism. This allows you to turn the crown and move the hands to set the time. The crown is attached to a stem, which goes into the watch and connects to a winding pinion, a gear that rotates with the stem to interact with other wheels that wind the mainspring.

The stem also has a sliding pinion, which moves depending on whether you’re in the winding or setting position. When in the setting position, the sliding pinion interacts with the setting wheel, transferring power to the intermediate setting wheel, minute wheel, and hour wheel, allowing you to move the hands forward or backward.

Canon Pinion and Hacking Mechanism

A key component in this process is the canon pinion, which connects the gear train of the watch to the setting mechanism and the hands. This component is friction-tight on the dial side of the watch. When you set the time, the canon pinion allows you to move the hands without moving the gear train. This is similar to setting a clock by manually moving the hands.

There’s another important function tied to the setting of a watch: the hacking seconds mechanism. This feature allows you to stop the second hand when you pull the crown out to set the time, ensuring you can synchronize your watch exactly to another clock. This is particularly useful in precise situations, such as for a fighter pilot syncing timepieces with others before a mission.

Hacking mechanisms typically involve a lever that connects the crown to the balance wheel, physically stopping the watch when you pull the crown out. There’s also a zero-reset hacking mechanism, where the second hand runs until it reaches zero and then stops, allowing you to pull the crown out at any time without worrying about the second hand's position.

Conclusion

Now that you know more about the setting and winding mechanisms, the next time you pull the crown out on your watch, you'll understand what each click does and how the movement pieces are interacting. There's a lot going on when you wind or set your watch, but now you'll know exactly what's happening inside the movement when you change the time.