November 1, 2025
While a mechanical timepiece will never achieve the pinpoint precision of a battery-powered quartz watch, a well-made spring-driven mechanical movement can still offer impressive accuracy. The quality of the movement—its materials, design, and craftsmanship—plays the most significant role in determining how well a watch keeps time.
In general, a high-grade mechanical watch will maintain time within just a few seconds per day. A medium-grade movement may vary up to 20 seconds per day, while lower-grade watches can gain or lose several minutes daily. This variation is normal for mechanical devices that rely on finely tuned balance wheels and escapements rather than electronic oscillators.
Jewel Count and Movement Quality
In the early days of pocket watches, the jewel count was often used as a key indicator of movement quality. Jewels—tiny synthetic rubies—are used as bearings at friction points to reduce wear and improve smoothness. In the late 19th and early 20th centuries, railroad-grade pocket watchesproudly displayed their jewel count, sometimes engraved directly on the movement or even printed on the dial.
However, not all jewel counts told the full story. Some early manufacturers exaggerated the number or placed jewels in unnecessary areas simply to market the watch as “high quality.” While a sufficient number of jewels is important for durability and efficiency, true precision depends more on how well the movement is designed, assembled, and regulated.
Positional error
Another important factor affecting accuracy is positional variation—the difference in rate when the watch is lying flat, standing upright, or worn on the wrist. This is sometimes called a personal error, since it depends on how the individual wears and handles the watch.
A watch left overnight on a nightstand may run slightly faster or slower than when it’s worn throughout the day. Over a 24-hour period, these variations often balance out, especially in well-regulated timepieces. High-grade watches are carefully adjusted in multiple positions (typically five or six) to minimize these differences. In contrast, lower-grade watches, such as early seven-jewel movements, can vary by as much as a minute between positions like “stem up” and “dial up.”
Manufacturers such as Rolex, Omega, and Breitling, along with the classic railroad-grade pocket watches, are known for their ability to maintain remarkable consistency across positions. Their attention to fine regulation and balance poising helps ensure minimal positional error and reliable daily performance.
Maintenance
Any mechanical watch that isn’t properly maintained will gradually lose accuracy over time. As bearing surfaces wear—including jewels, pivots, and gear teeth—precision naturally declines with age. However, well-crafted, high-grade watches can defy this trend; I’ve seen timepieces over 150 years old that still keep remarkably accurate time thanks to consistent care and proper servicing.
Conclusion
Mechanical watch accuracy is a balance of engineering, craftsmanship, and wear habits. From the jewel count to positional adjustments, every element of a movement contributes to its timekeeping performance. While a mechanical watch may never rival the precision of quartz, a high-quality, well-maintained mechanical movement remains a remarkable example of traditional horological artistry—accurate enough for everyday use, and admired for the impressive little machines that they are. For another take on this subject visit the page “How Accurate Should Your Mechanical Watch Actually Be?”
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