Regulation Marking — What This Mark Means
Markings on or near the movement's regulator indicating adjustment positions for timing accuracy. These are used by watchmakers to fine-tune the watch's rate.
What This Usually Means
The regulation markings indicate positions for the regulator mechanism that controls the watch's timekeeping accuracy. Typically shown as "+" and "-" (or "F" and "S" for Fast and Slow), these guide adjustments to the balance wheel's effective spring length. This is relevant only to mechanical movements.
Where to Find It
Located on the movement itself, near the balance wheel assembly. Visible through an exhibition case back or when the case back is removed. The markings are adjacent to the regulator lever, which is the small adjustable arm near the balance wheel.
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Common Variations
Common markings include "+/-" symbols, "F/S" (Fast/Slow), "A/R" (Advance/Retard), and graduated scales with numbered positions. Some high-end movements use free-sprung balance wheels with regulation screws instead of traditional regulators.
Common Misconceptions
Some believe these markings allow for owner adjustment, but regulating a watch requires precision tools and experience. Amateur adjustments can easily make accuracy worse. Also, "ADJUSTED" on a movement doesn't mean it was recently regulated; it indicates factory adjustment to specific positions.
What to Do Next
If your watch is running fast or slow beyond acceptable limits, take it to a qualified watchmaker for regulation rather than attempting it yourself. A professional can measure the rate in multiple positions and adjust accordingly.
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Frequently asked questions
Can I adjust the regulation myself?
It's technically possible but not recommended. Even tiny movements can swing accuracy by seconds per day. Professional regulation with a timegrapher is preferred.
What does 'ADJUSTED' mean on a movement?
It indicates the movement was factory-adjusted to meet accuracy standards in specific positions and temperatures.
How accurate should a mechanical watch be?
Most quality mechanical watches should be within -10 to +20 seconds per day. COSC chronometer certification requires -4 to +6 seconds.
Do quartz watches have regulation markings?
Some quartz movements have a small trimmer capacitor for rate adjustment, but it's far less common than on mechanical movements.
How often should a watch be regulated?
Regulation may drift over time. During a standard service (every 3-5 years), regulation should be checked and adjusted as needed.
What's a free-sprung balance?
An advanced regulation system that uses weighted screws on the balance wheel instead of a regulator lever, offering more precise and stable adjustment.