Regulation
Regulation is the fine adjustment that brings a mechanical watch closer to true time. By moving the regulator lever, a watchmaker alters the effective length of the balance spring, which speeds up or slows the oscillation and reduces how many seconds the watch gains or loses each day.
At a glance
- Who does it
- Usually a watchmaker
- Adjusting part
- Regulator lever
- Measured with
- Timing machine (timegrapher)
How fast a mechanical watch runs depends on how quickly the balance wheel swings back and forth. Regulation fine-tunes that swing rate to shrink the daily deviation, so it does not require a full teardown of the movement.
How it works
Most movements carry a regulator lever resting over the balance spring. That lever sets the effective length of the spring, and the balance bridge is often engraved with F for fast and S for slow to show which way to push it:
- Toward fast (F): the working spring shortens, the swing speeds up, the watch gains
- Toward slow (S): the working spring lengthens, the swing slows, the watch loses
A watchmaker reads the rate on a timing machine, nudges the lever a fraction, then measures again. Good work usually means balancing the rate across positions, the accuracy and deviation seen dial up, crown down, and so on.
When it is needed
A new watch can drift slightly over time, or its rate can shift after a knock. Regulation is normally carried out during maintenance, often alongside a full servicing. For a real-world look at how an automatic mechanical watch keeps time, read our Orient Mako 3 review.
Examples
An automatic that gains a few seconds a day can be brought close to true time at a watchmaker in minutes by nudging the regulator lever, a far smaller job than a full teardown.
View this watchIf a balance spring catches after a knock and the watch suddenly runs very fast, a watchmaker fixes the fault first, then regulates the rate again.
Comparison
Regulation and servicing are often confused but are different jobs.
| Option A | Option B | Notes |
|---|---|---|
| Regulation (rate adjustment) | Full servicing | Regulation only fine-tunes the rate; servicing strips, cleans, and oils the movement, then regulates it at the end. |
Related terms
Watches that show this
Frequently asked questions
Can I regulate a watch myself at home?
It is generally not advised. The regulator lever is tiny, and a small slip can throw off the rate or permanently damage the balance spring if you touch it. Doing it accurately needs a timing machine, so the job is usually left to a watchmaker.
Will regulation make my watch perfectly accurate?
No, a mechanical watch is never perfectly accurate. Regulation shrinks the daily deviation, often to within a few seconds, and improves balance across positions, but temperature and how you wear it still affect the rate somewhat.
How often does a watch need regulating?
A watch that holds steady does not need regular regulating. It is usually done only when the rate has drifted noticeably or during a full service. If your watch suddenly starts gaining or losing a lot, it is worth having a watchmaker check it.