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How does this happen!

by Jordan Ficklin

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I was going to write about Quartz Retrofits but than I came across this. The evil retrofit can wait for tomorrow. I knew this watch would be trouble when I saw the underside of the balance wheel.Swiss Cheese I call this Swiss Cheese. The indentations at 2 o’clock are normal. Nearly every other hole has been enlarged to remove weight. I suspect that somebody replaced the balance staff at some point and didn’t have a clue what they were doing when it came time to poise the balance wheel.

Poising the balance wheel: The weight of the balance wheel needs to be evenly distributed so that the center of gravity exists along the axis of the balance staff. Imperfections in manufacturing, the shape of the rivet holding the staff, and the roller are all reasons why it may not be perfect. Upon changing the staff (and moving the roller and reforming the rivet) it is necessary to poise the balance wheel. Corrections are made by removing a small amount of material until the center of gravity is in the center. (More on this when I write about my poising tools). The key word here is a little. One little hole on the underside of the balance wheel will usually do it.

In this case I don’t know what happened. My guess: the balance wheel was not properly riveted and so the wheel was constantly shifting and the individual working on the watch kept drilling holes to try and compensate. Exhibit 1:

The balance wheel is wobbling so bad it is disgusting. I removed the wheel and put it in my truing calipers to fix the problem:

Balance WheelBalance Wheel

You can see how much difference there is between the gap on the left and the one on the right after rotating the wheel 180 degrees. Turns out the wheel wasn’t bent it is just really loose on the staff and tilted. I guess I’ll have to re-staff it and try poising it. Wish me luck it’s already pretty nasty.

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