Dr. Ito's thorough analysis of mechanical watches!! Vol.2 ~ How do you adjust the accuracy of a mechanical watch? ~

Good evening everyone!

This is the second time,

How do you adjust the accuracy of a mechanical watch?

I will be talking about this topic.

In recent years, with the spread of smartphones, it has become commonplace for the time to be accurate, but when it comes to mechanical watches, each brand invests in high technology and costs to manufacture highly accurate watches. So how exactly do they make such high-precision watches? We would like to talk about the main methods of adjusting the accuracy and their features. Please read to the end!

How to adjust the accuracy of a mechanical watch

There are two main ways to adjust the accuracy of a mechanical watch.

There are two types of adjustment: the traditional "regulator" adjustment and the "free-sprung method" used in high-end watches including Patek Philippe.

I'm sure most of you have heard the term "regulator" before, but I think many people don't know how it works, so I'd like to explain it as simply as possible.

The "regulator system" adjusts the accuracy by changing the effective length of the hairspring. If we compare this to a pendulum, it is like stretching or shortening the length of the pendulum string to change the time it takes for it to go back and forth once. Because the adjustment range is wide, it can respond to various symptoms, but it is not suitable for fine adjustments and is not good at improving accuracy by seconds.

In contrast, the "free-sprung system" does not have a regulator, but is a mechanism that changes the accuracy by fine-tuning the position of the weight attached to the balance wheel. If we compare it to a pendulum, it is like fine-tuning the accuracy by changing the moment of inertia by inserting and removing a small screw attached to the weight without changing the length of the string. The free-sprung system was developed after the regulator, and is characterized by the fact that it allows for more delicate adjustments than the regulator.

A typical regulator (swan neck)

As the name suggests, this is a regulator made of curved parts like a swan's neck, fixed with springs and screws, and its delicate beauty fascinates mechanical watch enthusiasts. As it is used in high-end machines, it is also characterized by the fact that it is relatively easy to make fine adjustments to the accuracy.

This mechanism is also used in my beloved A. Lange & Söhne Lange 1 (first generation), and its beautiful design is breathtaking. It is one of my favorite regulators.

A typical free spring (Microstella Nut)

This mechanism was developed exclusively by Rolex, and while it is a simple design with four screws inside the balance wheel, it allows for extremely fine adjustments. As long as you have a special tool to turn the star-shaped screw called a Microstella nut, you can make fine adjustments to the nearest second without the need for special skills, and this mechanism is used in all current Rolex models.

Regulator or free-sprung, which is better?

So, which is better, the regulator or the free-sprung system? The winner is the "free-sprung system," which has been used for many years by brands with a reputation for high precision, such as Patek Philippe and Rolex.

As an engineer, I have adjusted the accuracy of many mechanical watches, and the "free-sprung method" makes it easier to refine the accuracy to the second. However, it has the disadvantage that the adjustment range is narrower than with a regulator, and it requires high technical skill and cost to manufacture, so there are pros and cons to both.

* Genuine "Cal.31" movement. No regulator and Microstella nut on the balance wheel.

*An aftermarket "Cal.31" movement. It does not have a microstella nut and has a regulator.

In recent years, it has been confirmed that aftermarket products that seem to be exact copies of Rolex movements have been sold. If you look at these movements, you will see that the structure and parts arrangement are identical, but the structure around the balance wheel, which is involved in adjusting the precision, uses a regulator that is different from the original Rolex. This ironically shows that the free-sprung system is difficult and expensive to manufacture.

summary

What did you think.

I think that in the future, the separation of high-end watches into free-sprung and other watches into regulators will likely continue. However, even brands that manufacture relatively inexpensive watches, such as Omega and Tudor, have begun to use the free-sprung system in their own movements, so the level of watchmaking is rising across the market, and the free-sprung system may become more common.

We hope that this article has been useful to you and has piqued your interest in luxury watches! If you have any questions, please feel free to ask us directly, and we look forward to hearing from you!

Look forward to the next one! See you next time!