Regulating Your Watch: From +25 to +5 Seconds a Day
How to Regulate Your Movement: Tuning Accuracy at Home
A mechanical watch that runs +25 seconds a day is annoying; the same movement regulated to +5 is invisible. Regulation — adjusting the effective length of the hairspring — needs no disassembly, just patience and a timegrapher (or a phone app and discipline).
What "Regulating" Actually Adjusts
The balance wheel oscillates via a hairspring. A regulator arm slides along the spring's outer coil: moving it effectively shortens or lengthens the breathing spring:
- Slow (+/- scale toward "-"):** move arm toward shortening → watch speeds up
- Toward "+" → slows down
That's the entire mechanism. The skill is in measuring honestly and moving tiny amounts.
Measuring: Timegrapher vs Free Methods
- Timegrapher ($30–100): clips on acoustically, shows rate, amplitude and beat error directly. Worth it if you'll own several watches
- App method: apps listen for ticks via microphone. Less precise but workable
- Manual method: sync against a reference clock, note deviation after exactly 24h. Repeat over 3 days for reliability
Measure in Positions
Mechanicals run differently by orientation because gravity acts on the balance:
- Dial up (flat on table)
- Crown down / crown up
You can't make all positions perfect. The classic compromise: regulate so dial-up runs slightly fast and pendant positions average near zero — wrist-wear mixes orientations anyway.
The Adjustment Procedure
- Open the caseback, locate the regulator arm near the balance (the two-position +/- marked lever — don't confuse with the beat-error stud holder beside it)
- Note current daily rate first
- Nudge the arm very slightly — a hair's width changes several seconds/day
- Reassemble, wear normally, measure again after 24h
- Iterate 2–3 times max per session; movements also drift as they settle after service
Realistic Targets
| Result | Verdict |
|---|---|
| -3 to +8 s/day mixed positions | Excellent for NH-class movements |
| +15 s/day | Noticeable but normal unregulated |
| >±30 s/day | Regulate, or suspect magnetization/major service need |
If regulation won't hold — rate swings wildly day to day — the problem isn't the arm: check our magnetization guide, then consider a full service.
Frequently Asked Questions
Does regulating void anything?
No seals broken beyond the caseback gasket you replace anyway. It's the most owner-accessible internal adjustment.
Beat error — should I fix that?
Only with a timegrapher showing large error; it requires repositioning the stud, which is one step beyond basic regulation.
My watch runs fast only at night face-up.
Positional variance — store it crown-down overnight to average out, or accept ±10s total spread.