Good things come to those who wait, which probably explains why procrastination feels so good. Fortunately, waiting around is an important step in watch adjusting.
When a watch is freshly serviced—squeaky clean, newly oiled, and ticking away happily—it isn’t ready for adjusting. Before adjusting a watch to positions, let it run for a day or two. Watches, like fruit, need to ripen.
Watches need to “run in” for a while before they reach a stable, consistent rate. Elgin put it nicely in this handy insert they included with their DuraPower mainsprings.
If you can’t read the image, it notes:
…As a newly assembled or repaired watch “runs in” to its stable friction condition, there is a tendency for the balance motion to increase above that initially present.
In short, the amplitude will increase as the watch runs in. And, as we have learned, rates in different positions are strongly affected by amplitude.
Imagine adjusting a watch almost perfectly right after cleaning it. The amplitude will be lower, so although the rates might be perfect at that point, they won’t be a few days later when the amplitude is higher.
Why the Boost?
As the watch runs, the lubricants become more evenly distributed around their moving parts, reducing friction and boosting amplitude.
In fast-moving parts, like the balance and escape wheel pivots, the oil “beds in” fairly quickly. In slow-moving parts—the center wheel’s pivots, the mainspring coils (if you lubricated the spring), and the mainspring’s barrel arbors—it will take more time.
A big part of the gain, I suspect, comes from the pallet jewels. Modern pallet jewel lubricants work wonders for amplitude. It takes some time for the oil to distribute evenly on all the locking and sliding surfaces of the escape wheel teeth.
For an example of the difference a day makes, here’s a recent patient: an Elgin grade 315, which is a 15 jewel, 12-size pocket watch. Right after getting it ticking, I fully wound it and measured its amplitude when dial up.
An amplitude of around 280 degrees is nothing to scoff at in a 90 year old watch. But here’s what we have 24 hours later:
The amplitude dial up increased by 40 degrees, and now we’re really swinging.
In short, you might be itching to get going on a freshly cleaned and assembled watch, but good (and consistent) amplitude comes to those who wait.