Regulating is moving the regulator pointer to fast or slow adjusting the rate. A watch may run at different rates in different positions. The task of regulation is to adjust it so that the average running rate is as close to a zero error between the most common positions. Thus, the correct setting for the regulator will be slightly different for each owner, depending on how the watch is worn or carried (this is sometimes referred to personal error). In the shop a timing machine is used to quickly adjust the rate.
If your watch is not keeping good time, you can adjust the regulator yourself. A slight nudge (toward the F or fast will speed the watch up, and toward S or slow will slow it down). Then let the watch run for a few days to see how much the rate was affected. Higher grade watches utilize a micrometer regulator and afford more fine control via a small screw. These are a bit more difficult to adjust, as the screw can be tight, and the small screw driver can easily slip. If in doubt, let an expert adjust the regulator (see images below).
Adjusting a watch involves procedures that include ensuring the balance wheel is ‘balanced’ (poised), adjusting the hairspring, shaping the balance pivots and adjusting how the hairspring is attached to the balance wheel.
The three critical adjustments are for position, temperature (the ability to keep good time over a range of different temperatures), and isochronism (the ability to keep an even rate over the life of one spring wind, typically 24 hours). An un-adjusted watch should run at a reasonably constant rate in two to four positions. The primary positions for a pocket watch are stem up, face up, stem right and left. Medium grade wrist watches are adjusted for stem down-left-right and face up. High grade wrist and pocket watches are adjusted to vary no more than 5-10 seconds between six positions.
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