Avoiding Common Errors When Winding Antique Spring Clocks

Many collectors believe that if a clock feels "tight," you should keep winding until it can't turn anymore. That's a dangerous assumption. This post covers the specific mechanical errors that lead to broken mainsprings and why your winding technique matters for the longevity of your collection.

How Much Tension is Too Much for a Spring Clock?

You should stop winding the moment you feel a firm, consistent resistance—never force the key past that point. If you feel a sudden "give" or a click, you've likely bypassed a safety notch or hit a limit. Forcing it isn't just stubborn; it's expensive. A snapped mainspring can wreck an entire movement, and replacing one often costs more than the clock is worth.

It's easy to get carried away when you're excited about a new piece. But remember, these old machines aren't built for brute force. They rely on precision. If you're working with a high-end mantel clock, the tension is already high. You don't need to add more.

Why Do My Winding Keys Feel Stuck?

A stuck key usually means the clock is fully wound or there is debris in the winding arbor. Most mechanical issues stem from either a lack of lubrication or a physical obstruction. If the key won't budge, don't use a wrench or pliers to force it. That's a one-way ticket to a broken gear.

Check these three things before you call a professional:

1. The Direction: Ensure you aren't winding in the wrong direction (some older clocks are directional).
2. The Key Fit: Make sure the key is seated deeply and squarely in the arbor.
3. The Resistance: If it feels "crunchy" rather than smooth, the oil has likely dried up.

If the movement feels gritty, you might need to look into protecting your pendulum and movement from environmental factors. Dust and old oil are the enemies of smooth motion.

What Are the Signs of a Broken Mainspring?

The most obvious sign is that the clock stops running shortly after you wind it, or you hear a loud, metallic "bang" during the winding process. If the hands stop moving despite the clock being recently wound, the spring has likely lost its tension or snapped entirely.

Here is a quick comparison of healthy vs. problematic winding sensations:

If you're ever unsure about the internal state of a piece, especially when identifying genuine French mantel clocks, it's better to be cautious. A little patience goes a long way in preserving these mechanical wonders.