The old "Over-winding the Clock" Myth

I’d be a rich man if I had a dollar for every time a clock owner dropped-off their clock with the phrase “It was running fine until (insert the name of the manliest man in the house) over-wound it”!
This reminds me a bit of the fact that light bulbs will most always “burn-out” at the moment the switch is thrown. Is it fair to say that the last person to flip the switch over-threw it? Of course not! The filament becomes weak from hours of tungsten being tossed-off, and it just happened to give up the ghost when the cold filament received the shock from the rapid heating that illumination brings.
While it is technically true that a mainspring can become damaged by repeated over-tightening , which is the term that Clockmakers use for winding the spring until it is tight, and then continuing to tighten “for good measure”. It’s unlikely, however, that the last person to wind the clock was entirely the cause of the spring failure.

Take note of detail #25 in the image above. This is an x-ray view of a mainspring inside of a spring barrel. The spring is attached to the winding arbor #13, which is where the key or crank is placed for winding. When the spring is wound it is coiled tightly around this arbor. The other end of the spring has a small hole which is hooked over a small hook or stud, which is riveted into the interior wall of the barrel . The hole in the spring can become fatigued over years of repeated "over-tightening", and likewise the stamped hook or riveted stud can also break free.

So is over tightening a main spring a myth? Not really. But it isn't the most common reason for clocks to stop. Usually it's as simple as the need for a good overhaul.

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