Timing discrepancy between a watch's ticks and tocks, indicating escapement imbalance that affects timekeeping accuracy.
Beat error is the difference in time between the tick and tock of a watch, indicating the balance wheel isn't oscillating symmetrically. Ideally, the tick-tock intervals should be perfectly equal. Beat error is measured in milliseconds or degrees, with 0.0ms being perfect. Values above 0.5ms-1.0ms can affect accuracy and should be corrected.
Beat error results from improper balance wheel positioning on the staff, uneven hairspring tension, misaligned pallet fork, or impact damage. It can occur during assembly, from drops/shocks, or gradual component wear. Even small misalignments create asymmetric oscillation, causing one beat to be longer than the other.
Yes, watchmakers correct beat error by adjusting the balance wheel's position on its staff or fine-tuning the hairspring's attachment point (collet). This requires specialized tools and expertise. Modern timing machines measure beat error precisely, guiding adjustments. Correction improves accuracy, reduces position error, and extends movement longevity by ensuring balanced operation.