Most modern automatic watches today can be hand-wound. So do all hand-wound (only) mechanical watches. But if you’re just started as a watch enthusiast, it can be hard to know what you should or shouldn’t do, and if you can overwind a watch.
Can you overwind a watch? You can’t over-wind modern automatic watches. The winding mechanism will simply decouple from the mainspring when it is fully wound, winding into infinity. This is when you should stop winding your watch.
Beware of low quality and very old watch: they can still use older mechanisms that were not designed to protect the mainspring from over-winding.
Manual winding watches will let you know when the mainspring is fully wound: you will feel a resistance and the winding stem will stop moving.
Make sure to know exactly what type of watch you have before winding it manually, as well well as the consequences of winding it completely and what are the causes if it stops.
The difference between an automatic and a manual winding watch
First of all: manual winding and automatic watches are both mechanical watch. Meaning, they feature a complete mechanical mechanism (called movement) that runs the watch.
None of them require a battery, as the power needed for a mechanical movement to run is stored in the mainspring.
In order for the mainspring to deliver power, it has to be wound. This is done either by hand or automatically, depending on the type of mechanical watch.
A manual winding watch is a mechanical that you have to wind by hand for the movement to start running (hence the name). Depending on the power reserve of the watch and how much you wound the mainspring, the watch will stop sooner or later.
In order to keep it running, you will have to wind it at regular intervals.
On the other hand, an automatic watch features a mechanism that winds the mainspring automatically when you are wearing the watch. The movement of your arm and wrist will put your watch in different positions.
Meanwhile, a weighted rotor inside the watch will always balance itself due to gravity. By doing so, it will make a part of the mechanism move in order to automatically wind the mainspring.
If you keep your automatic watch on your wrist all day long, remove it for the night, and then put it again on your wrist the next morning, your automatic watch will run forever without you doing anything.
This is because the power reserve of a mechanical watch is 38 hours or more.
Can automatic watches be over-wound?
No, they can’t. Automatic watches have a mechanism that winds the mainspring every time you move, but only if it’s not already fully wound. When the mainspring is fully wound, the rotor inside the watch will stop spinning in the direction in which it winds the mainspring.
Because you are moving your arm all day long, watch manufacturers had to find a way to prevent you from accidentally over-winding the mainspring.
You just can’t control the amplitude and amount of your movements all day every day, right?
What about hand winding an automatic watch, then? Some automatic watch can’t be hand-wound (the Seiko SKX013 is a notable example – read my full review here), but most can.
Can you over-wind your precious automatic timepiece by hand?
No you can’t. If the mainspring is not fully wound, then turning the crown (the outer part of the movement connected to the winding stem) will simply wind the mainspring as it should.
If the mainspring is already full wound, turning the crown will have no effect. As a matter of fact, the mechanism will disengage the winding action from the mainspring, keeping it safe.
Is it dangerous to fully wind a mechanical watch?
No, it’s not dangerous. Most mechanical watches (automatic or manual winding) feature at least a 38 hours power reserve. Many more watches now feature a 70 to 80 hours of power reserve.
Some more refined pieces have a mainspring that can make the watch run for 7 to 30 days! Of course, this is only featured on high-end watches.
And the reason is simple: the more complicated the watch (with a lot of complications like the day, date, tide, moon phase, week number, month, year, …), the more difficult it is to set it up.
Yet you don’t wear your watch every day, nor do you wear it all day long.
This is why, in order to keep all those settings, manufacturers sometimes feature a very large power reserve. The watch will be running while waiting for you to wear it again or wind it again, even if a few days passed between usages.
But in order for your watch to reach that full power reserve, the mainspring can be fully wound, especially when you don’t intend to wear your watch for a few days, but want to keep all the settings correct.
Unless you’re very rough, you really can’t go past the point where you wind the mainspring too much. They are quite strong parts that are tough to break.
And if you actually break something by winding the watch, this is because:
- you went way past the resistance of the watch (which is almost impossible without using a tool like pliers, for example)
- a part in the watch was already in bad condition and was about to break anyway
- your watch needs servicing and the lubricating oils settled inside the movement. In that case, your watch should be sent to the manufacturer or a watchmaker for checkup and maintenance.
My automatic watch stops overnight!
This is a completely normal behavior. If your watch ran out of power when you decide to wear it again, just start it again. You could either gently shake the watch (in order to spin the rotor, hence using the automatic winding mechanism), or you could hand wind it with a few turns of the winding crown.
The thing is: with just a few turns of the crown or a 30 seconds shake, you’re only giving your mainspring a few hours worth of power.
It’s not a problem per se, as a watch can run just fine with a very low power reserve. As long as the mainspring is not fully unwound, the movement will run.
But on some days, you might not move your arm enough for the mainspring to wind more than 2 to 4 hours worth of power.
I found this to be especially true on weekdays where I spend all my time working on my computer and then driving back home on the highway. No wrist action there whatsoever!
So because the mainspring is not wound to provide at least 12 hours of power reserve (a typical night + some time off before and after the night), you can find that your watch stopped during the night.
This is normal, it’s not broken. This happens to me all the time when I wear my Seiko SKX013 and do only “desk diving” work.
To prevent this from happening, hand wind your watch before going to bed. And if you can’t hand wind it (like my Seiko), just shake it for 2 minutes. It should be running just fine when you’ll wake up the next morning.
How often should you wind a mechanical watch?
You’ll have to wind most manual winding watches every morning or every night. The majority of watches have around 40 hours of power reserve, so waiting 2 days to wind it will make it stop. You can wind watches with 70 hours of power reserve every 2 days.
If you wear an automatic watch every day, you don’t have to wind it at all. Your power reserve will be full most of the time, and not wearing for the night won’t make it stop.
In any case, always remember to stop when you feel a resistance when winding your watch.
How much should you wind your watch
You will reach the maximum power reserve by turning the winding crown about 30 to 40 times. That translates roughly to 30 to 40 half revolutions of the crown. This is true for an automatic or a manual winding watch.
Of course, this will vary on the type of movement that is powering your watch and your watch’s power reserve.
- If it’s a manual winding watch, stop as soon as you feel a resistance.
- If it’s an automatic watch, the mechanism may make a different sound (a small clicking sound, most of the time) when the mainspring is fully wound.
Also, the feel of winding your watch may become a little different. This is when your power reserve is full. Remember: you can’t over-wind most modern automatic movements.
In case of doubt, 30 turns is a good starting point. Work your way up from there.
My mechanical watch won’t wind!
A watch that can be hand wound but doesn’t hand wind anymore need to be checked by the manufacturer or a competent watchmaker.
If your mechanical watch won’t wind, there are a couple of reasons for that:
- the automatic mechanism of your automatic watch is broken or disengaged
- parts or gears are misaligned, making the crown and winding stem wind into infinity
- parts or gears are broken and need servicing
Unless you’re in a hurry because you want to wear your watch for a special occasion, there is no rush.
Almost all parts can be sourced for pretty much all mechanical movements, automatic or manual winding ones (especially famous movements made by ETA, Sellita, Miyota, Valjoux, …).
And if you have a really old timepiece and that the parts are not available anymore, it’s always possible to find a master watchmaker to create it or build it from scratch again. (But it’s going to be very expensive.)
Watches are tough little gems that will be running by your sides for decades to come, if you take care of them.
If you want to know everything about automatic watches, check out the complete watch winding guide!