Timing tolerances - a guide to understand how they work

Archer

Why?

Deafboy

Because!

Lift angle depends on the location of the banking pins.

Archer

That’s some fine circular logic...

Deafboy

I hypothesized a watch model with fixed banking pins would have less sample-to-sample variation of lift angle than a model with adjustable pins.

Professor

When a movement is marked "unadjusted" I assume that means it was not adjusted to the various positions, but surely it was adjusted to keep good time in at least one position.
I've read that old time railroad approved pocket watches were usually carried in a pocket narrow enough the when the watch was inserted crown up it would stay that way, so these were adjusted for best accuracy in a crown up position. Accuracy in other positions, though tested, was secondary since even while sleeping the watch would be hung or stood in a crown up position.

I've seen unadjusted markings on movements of some high grade wrist watches. Did the movement manufacturer leave adjustment for positions up to the jewelers who sold their watches, or to whoever first cased the movement?

J jmnav

In practical terms, no need for it, as it can be implied. You know (or can get) what the tolerances and drifts are in the static positions. Now, you go to your watch expert of choice and tell him on my wrist, this watch goes 15s/day too fast (or whatever): he can (or should) be able to make an informed guesstimate between the static values and values on your wrist to further regulate your watch (that's what regulation is for, after all). Worst case scenario, it will take a few travels to the watch mechanic to properly regulate it.