There are two situations where the term over-winding might be used:
1. You force and break the watch (most likely the mainspring) while winding it.
2. The watch is fully wound, but it doesn’t run. It’s impossible to wind it any further, so it must be over-wound.
1. Break a watch by winding it too much
The mainspring in a manual wound watch is secured on both ends. One end is secured to the barrel arbor, and the other end is secured to the barrel. The mainspring has a hook or an extension spring that locks in a groove in the barrel wall. This hook or extension spring is also called the bridle.
When you wind a manual watch, you’ll slowly feel the mainspring building up resistance. It’s best to slow down when you start to feel resistance and gently continue to wind until you can’t wind it any further.
Some hand-wound watches have some protection against over-winding.
Rolex, for example, has a system in some of their watches that uses three notches inside the barrel wall. The spring clings to one of those notches until the pressure gets too high. Then it will just “jump” to the next groove and so on.
The mainspring in an automatic or self-winding watch is only secured on one end, the barrel arbor. The other end has a kind of bridle to it, but it doesn’t have a hook.
Instead, it uses an extra piece of mainspring (also called the bridle) to push against the wall of the main barrel. This creates friction so that the mainspring can be wound. However, if the kinetic energy built up in the mainspring grows bigger than the friction on the barrel wall, it’ll slip.
The barrel wall is made of brass or aluminum and is, therefore, quite “slippery.” To increase the friction, the barrel wall needs to be treated with a thin layer of braking grease.
Newer mainspring barrels have small notches inside the barrel wall to help the bridle to hold on and increase the friction.
So, can you break a watch by over-winding it?
Yes, in theory, you can over-wind a hand-wound watch. However, that has to do with the condition of the mainspring. A mainspring in good condition can withstand much more pressure than you can exercise.
Also, you have to be very stubborn and ham-fisted to keep trying to wind your watch when it’s resisting. If you break the mainspring, it was in bad condition and it needed to be replaced anyway.
You can’t over-wind an automatic watch because it has built-in safety precautions to prevent precisely this.
2. It’s over-wound because I can’t wind it anymore and it doesn’t run
You’ll see this one in plenty of ads on eBay and other auction sites. I’ve heard it on collector fairs and flea markets, as well.
It’s a very lazy way of saying that the watch isn’t running and you don’t know why.
Common reasons for a watch to stop
- Broken balance staff
- Tangled balance spring
- Presence of dried and thickened oil
- Presence of dust or dirt or a hair
- Severely magnetized
- A damaged, bent or worn pinion
- A broken, bent or worn tooth on a wheel
- Loose, cracked or worn bearing jewel
- Etc. Etc.
There are hundreds of reasons for a watch to stop, but over-winding your watch isn’t one of them. Remember that, because it sounds like a straightforward repair, but it’s not. It could be any one of those hundreds of reasons.
The watch needs to be completely overhauled, and it’ll probably need some new parts as well.
Have you ever bought a watch that was supposed to be over-wound? What turned out to be the actual problem?