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Good evening, everyone!
For this second installment,
"How do you adjust the accuracy of a mechanical watch?"
We'll be discussing this topic. In recent years, with the spread of smartphones, it's probably taken for granted that time is perfectly accurate. However, when it comes to mechanical watches, various brands invest significant technical skill and cost to produce highly accurate timepieces. So, how exactly are highly accurate watches made? I'd like to talk about the main accuracy adjustment methods and their characteristics. Please read to the end!
Mechanical Watch Accuracy Adjustment Methods
There are roughly two main methods for adjusting the accuracy of mechanical watches.
One is the traditional adjustment using a "regulator," and the other is the "free-sprung balance" system used in high-end models, including those from Patek Philippe.
Many of you may have heard the term "regulator" but aren't familiar with its mechanism, so I'll try to explain it as simply as possible.
The "regulator system" adjusts accuracy by changing the effective length of the hairspring. To illustrate this with a pendulum, it's similar to changing the time it takes for one swing by lengthening or shortening the pendulum's string. While it offers a wide range of adjustment for various issues, it's not well-suited for fine-tuning and struggles to achieve accuracy down to the second.
In contrast, the "free-sprung balance" system has no regulator. Instead, it adjusts accuracy by fine-tuning the position of weights attached to the balance wheel. To illustrate this with a pendulum, it's similar to fine-tuning accuracy by varying the moment of inertia, without changing the length of the string, but by adjusting small screws on the weights. The free-sprung balance was developed after the regulator and is characterized by its ability to make more delicate adjustments than the regulator.
Representative Regulator (Swan Neck)
As the name suggests, this regulator is crafted with curved parts resembling a swan's neck, secured by a spring and screw. Its delicate beauty captivates mechanical watch enthusiasts. Characteristic of its use in high-end models, it also allows for a relatively easy fine adjustment of the system.
This mechanism is also employed in my beloved A. Lange & Söhne "Lange 1 (first generation)," and its sculpted beauty is truly breathtaking. It's one of my personal favorite regulators.
Representative Free-Sprung Balance (Microstella Nut)
This mechanism, uniquely developed by Rolex, allows for extremely precise accuracy adjustments with a simple construction featuring four screws placed within the balance wheel. With a special tool to turn the star-shaped screws known as Microstella nuts, fine-tuning to the second is possible without requiring specialized skills. This mechanism is adopted in all current Rolex models.
Which is superior: Regulator or Free-Sprung Balance?
So, which is superior: the regulator system or the free-sprung balance system? The "free-sprung balance" system, which has been adopted for many years by brands renowned for their high precision such as Patek Philippe and Rolex, takes the prize.
As a technician, I have performed accuracy adjustments on numerous mechanical watches, and the "free-sprung balance system" makes it easier to achieve precision down to the second. However, it also has drawbacks: a narrower adjustment range compared to the regulator, and higher technical skill and cost required for manufacturing. So, both have their pros and cons.
*Genuine "Cal.31" series movement. No regulator, with Microstella nuts on the balance wheel.
*Aftermarket "Cal.31" series movement. No Microstella nuts, with a regulator.
Furthermore, in recent years, it's unfortunately been observed that aftermarket movements, almost perfect copies of Rolex movements, are circulating. While the structure and arrangement of parts in these movements are almost identical, the structure around the balance wheel, which is responsible for accuracy adjustment, mostly employs a regulator system, unlike genuine Rolex. This ironically illustrates how difficult and costly it is to manufacture a free-sprung system.
Summary
How was it?
In the future, it is highly likely that a clearer distinction will emerge, with high-end models utilizing the free-sprung balance system and others employing the regulator system. However, even brands manufacturing relatively affordable watches, such as Omega and Tudor, are starting to adopt the free-sprung balance system in their in-house movements. This suggests that the overall level of watchmaking in the market is rising, and the free-sprung balance system might eventually become more common.
I hope this article provided valuable information and sparked even a little interest in luxury watches! If you have any questions, please feel free to ask directly. We look forward to your visit or inquiry.
Stay tuned for the next installment! See you then!
