There are 2 situations where the term over-winding might be used:
1. Over-wind a watch so you force and break the watch (most likely the mainspring)
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 far
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 extensions 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 start to 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 do have some sort of protection against over-winding.
Rolex, for example, uses a system in some of their watches that uses 3 bigger notches inside the barrel wall. The spring clings to one of those notches until the pressure gets too high. Then it will simply “jump” to the next notch 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 sort 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 will 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 of the mainspring 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 but it shouldn’t be possible.
A mainspring in good condition can withstand much more pressure than you can exercise. Also, you have to be very stubborn and clumsy to keep trying to wind your watch when it’s clearly resisting.
If you break the mainspring it was in a bad condition already and it needed to be replaced anyway.
You can’t over-wind an automatic watch because it uses safety precautions to prevent exactly this.
2. It’s overwound 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.The watch is overwound = The watch is not running and I have no idea why.Click To Tweet
The watch doesn’t run and you can’t wind it anymore (because the bridle clings to the barrel wall and the mainspring is fully wound).
It’s a very simple 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 broken, bent or worn pinion
- A broken, bent or worn tooth on a wheel
- Loose, cracked or worn bearing jewel
- Etc. etc.
Remember that, because it sounds like a very easy repair but it’s not. It could be anyone of those hundreds of reasons.
The watch needs to be completely overhauled and it will 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?