While I love the beauty of diamonds, gold, and gems, I also love the more scientific inner workings of a timepiece. From time to time, in a series called Watchmaking 101, I’ll feature a particular aspect of watches that will hopefully interest watch collectors and novices alike.
Manual or Automatic Timepiece: What’s the Difference?
A tiny spiral spring of metal ribbon, gently coiling and uncoiling, is the key to power inside a watch. The mainspring, as it unwinds, provides power to the movement to keep the hour and minute hands moving. (Other parts of the watch regulate the time.)
In a manual wind watch, we turn the crown clockwise to wind the mainspring tightly. As it unwinds during the next 24 hours, it powers the watch. With an automatic, or self-winding movement, the rotor constantly winds the mainspring.
To understand how the rotor works picture a grandfather clock. The weights below the clock swing back and forth, and this motion winds the clock’s mainspring. Now picture this same movement inside a watch case. The rotor, typically a heavyweight metal with a kidney bean shape, is pinned to the center of the movement and swings freely both ways with every slight movement of the watch. This constant motion creates a self-wound mainspring. In other words, there’s an amazing tiny motor inside every watch case!
Keeping the Movement
While a manual wind watch must be wound each day, an automatic watch should stay wound as long as it is actively worn every day. However, automatic movements can also be manually wound, just as a manual watch is wound, to start the day off with full power and the most accurate timekeeping. Manually winding and setting an automatic movement after a long weekend in the jewelry box will ensure good timekeeping. Ever see someone shake their watch? This provides a small amount of power to the movement but will not provide a full wind that powers accurate timekeeping.
How long does an automatic watch stay wound? What’s the difference between mechanical and quartz movements? Stay tuned for our continued watchmaking series.
