# ELI5, How does a mechanical watch continue to keep time as it’s winding?

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As I understand it, the winding of the watch adds tension to a spring that exerts force in the opposite direction of the wind to make the watch tick. The thing I can’t figure out here, is how while adding tension to the spring, it’s able to unwind in the opposite direction. I’ve spent the last fifteen minutes looking into this and every “how do watches work” video I can find conveniently skips over this part. Thanks in advance.

In: Engineering

Ah yeah, it’s not the opposite direction.

You wind from one side of the spring coil, probably the inside, and the other side is what drives the watch mechanism.

Like imagine pulling a car with a long spring. You walk forward a bit, the spring stretches. The car creeps up while you wait. When it gets too close you walk forward a bunch more.

The key thing with watches is the escapement that keeps constant time no matter what the tension is. As long as the tension isn’t removed entirely it will continue to tick at constant time.

The outside of the spring is connected to a gear that’s driving the gear train. The inside of the spring is connected to a ratchet that winds it from the inside as the outside unwinds.