Jewel Theives

There used to be a common myth, what we would call a meme today, that unscrupulous watchmakers sometimes stole the jewels out of the watches they repaired.

The jewels in watches are synthetic sapphires and rubies, typically, used as bearing parts, this material being extremely hard and resistant to wear. The jewels in watches are completely practical, not ornamental, and they have very little monetary value. And besides that, a watch will not run without them, so the customer would probably notice if they were stolen.

I still occasionally hear this tale. Not long ago I serviced a watch for a customer who planned to surprise the watch's original owner, their grandfather. I was told by the customer that the grandfather swore that a watchmaker had stolen the jewels back in 1960s, when the watch was last serviced. Of course I found this not to be the case.

Recently, I came across this example of a watch which, for some reason, has indeed had a couple jewels rather roughly removed. In the close up we can see two jewel-less bearings, and third one still intact. It should be clear that this watch would not run with those two jewels missing and the corresponding gears thus floating all over freely.

When is a Watch Over-Wound?

There is no such thing as over-wound.

Winding a watch is turning the mainspring around its arbor.  As the arbor turns, the coils of the spring are pulled from the outside of the barrel, inward.  It wraps around the center arbor until it gets to the end of the spring and then you can't turn it any further.  It's like wrapping a string around a stick, you can't wrap more than the whole string.

At the end, it's fully wound.

This is like fulling the gas tank of a car.  Full is full, you can't add more.  And along those same lines, saying a watch is "over wound", which I hear almost daily, makes no more sense than saying a car won't start because the tank has been filled.

Today, we can just wind watches occasionally, for the pleasure of running them.  But when vintage mechanical pocketwatches were in common use, they were designed to be fully wound once each day, at about the same time - in the morning for example.

On a full wind the watch will run in the ballpark of 30 hours.

Pocketwatch Over-wound?

For the record, there is no such thing as "over-wound".

A watch is designed to be wound fully.  A watch is fully wound when its mainspring is wound around its arbor to the end of the spring, and there is no more spring to wind.  At that point, the crown (or key) will not turn any further.

Saying a watch will not run because it is over-wound is like saying a car won't start because the fuel tank is over-filled.  The tank is either full or it's not.  You can not add more if its full.  A watch is either fully wound or it's not.  You can not wind it more if it is fully wound.

If a car won't start, there's a reason.  If a watch won't run, there's a reason.  But there's no such thing as "over-wound".

I used to think that this idea of over winding a watch was a modern misunderstanding.  But just the other day I ran into a reference to this persistent myth in an article written in the 1920s.  So it seems to have been with us for awhile...

At any rate, there is no such thing as "over-wound".