The Most Dangerous Game

Vintage watches can be stressful to service since their parts are out of production, and losing one means big trouble. This is doubly true for springs.

Shock springs on vintage pieces have been sitting under tension for decades, and are just begging for their freedom. One careless move, and they're gone in an instant.

Shock springs are absurdly small pieces of metal. Here's one with a 1.00 mm screwdriver blade and a human hair for scale. 

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They're so thin, they're almost two-dimensional.

Shock springs might not look like much, but they have a lot of boing left in them, and almost no mass. They're so light that if they shoot away, you won't see it happen. One moment they're in place, the next, they're somewhere in the stratosphere.

A way to protect against such behavior is to detain them with something heavy and sticky, like a tiny ball of Rub-Off. Rub-Off is similar to sticky-tack, and we use it to pick up lint or spattered oil from a movement. In this case, the smallest ball can be stuck to the shock spring, increasing its mass exponentially, and making the spring sticky so it won't ricochet.

While working on the Omega 662, the dial-side shock spring liberated itself from the movement with an imperceptible sproing as I removed the balance jewels. Luckily, it didn't go far.

These Incabloc springs clip in to the setting on one side, and the free ends clip into the other. It's just a matter of re-clipping the spring into its recesses, but on a movement this small, it gets hairy.

This is the most dangerous part of the process. The hinge is set into place (these spring settings are old and don't "clip" well any more, which is why it sprang away in the first place), and the balance jewels are oiled and in place below it. Note the Rub-Off acting as my safety net.

Bending the spring over the jewel to the other recess will put it at its maximum tension, and if it gets loose now, it will really fly.

All clipped in! Don't be fooled by the magic of editing—this took several tries to get in place. The spring launched itself repeatedly, but didn't go far thanks to its sticky companion. 

Watchmaking student at the Lititz Watch Technicum, formerly a radio and TV newswriter in Chicago.