From the Bench: Can I Wind My Automatic Watch?

Mar 11, 2024

Popular wisdom says that you shouldn’t wind an automatic watch… But why? And is that even true? Let’s take a look.

People’s primary worry is that winding an automatic watch will damage the movement in some way. There’s a kernel of truth to this, but it’s not as dangerous as people think.

The first worry is that winding an automatic watch can damage or break the mainspring. We’ve talked about this previously, but TL;DR, you can wind a modern automatic mainspring forever without any problems.

The second concern is that winding the watch will damage something else in the geartrain. This can sometimes be a problem, but not with Oak & Oscar watches, so let’s look closer.

Winding mechanisms are usually the most robust part of a watch movement because they have to deal with the most violent force a watch will encounter: YOU. This means that most components are thicker, robust and made of steel to resist the torque from winding.

Traditionally, it’s steel all the way back, from the stem to the ratchet wheel. While most geartrains in a watch alternate brass and steel to minimize friction, the increased strength of steel is worth any possible frictional losses, since your fingers can just power through it.

Automatics change this calculation. Since the ratchet wheel has to be powered by both the winding train and the automatic module, it needs a different design. On many watches, this means that the ratchet wheel becomes thinner and finer, and sometimes it’s even made of brass.

This design change can lead to some compromises, and here we can find some potential sources of problems.

It’s most problematic in a movement like the ETA 2824 or Sellita SW200 series, where the ratchet wheel is made of fine-toothed brass, while the crown wheel is coarse-toothed steel. If wound roughly, the crown wheel’s steel teeth can potentially jam or bend the finer brass teeth on the ratchet wheel.

The crown wheel also doubles as a “wig-wag” that oscillates in and out of position to engage and declutch the ratchet when the automatic is running, meaning that its big steel teeth may not perfectly re-mesh with the ratchet wheel’s fine brass teeth when wound again.

Manual-wind versions of the 2824—like the 2801—use a thicker steel ratchet wheel to avoid any issues, since it will be wound regularly.

We don’t use any version of these movements at Oak & Oscar, so let’s look at the ones that we do use.

These issues do not occur in a 2892 or SW300. In these movements, the winding train is more complicated, with the crown wheel turning pair of intermediate wheels, one of which provides a reduction ratio just before its pinion turns the ratchet wheel. The small pinion provides a much gentler torque to the ratchet wheel, and never comes out of engagement as a clutch, so it is extremely unlinkely to jam or bend anything on the ratchet wheel.

The Soprod A10 or C125 movements are even more robust, with steel wheels and pinions all the way through the winding mechanism, including the ratchet wheel. Since everything is coarse and steel, it resists breakage, though the steel-on-steel winding friction does cause some different wear that we’ve covered elsewhere.

A final potential failure point is the automatic itself. Winding the watch will run parts of the automatic system backwards, so they spin pretty quickly on their pivots. This isn’t a problem if everything is properly lubricated, but it can cause some wear.

Of course, the great caveat with any of this is that a dirty movement with grit or debris inside can jam up and break if wound roughly, so if you’re winding your watch and it feels rough, DON’T power through it. Remember, you’re strong enough to break a watch, so be gentle.

But Oak & Oscar wearers, don’t worry too much. Just be careful not to force anything, and you should have no problems winding your watch by hand.

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From the Bench: Can I Wind My Automatic Watch?