Dr. Ito's thorough analysis of mechanical watches!!

Good evening everyone!

My name is Ito, an appraiser and watch repair technician at Commit Ginza.

I worked as a watch repair technician for a certain famous brand for 20 years, but then I had the chance to start my career as an appraiser at Commit Ginza. This time, I decided to use my experience as a technician over the years to write an article that would allow me to share information that is not usually available to everyone, such as explanations of movements, how to use complicated watches, and information on daily maintenance. I will also be sharing behind-the-scenes information that only a technician would be able to find out, so I hope you enjoy reading!

Now, the first memorable event is,

"Rolex: Which is better, the Cal.31 series or the Cal.32 series?"

I would like to talk about this topic.

The "Cal. 31 series" movements, which began with the "Cal. 3155" installed in the "Day-Date" in 1988 and ended with the "Cal. 3131" installed in the "Milgauss" Ref. 116400GV", have put an end to their long active life.

On the other hand, nine years have passed since its debut in 2015, and the "Cal. 32 series" movement, which is now installed in a variety of current models, is reaching the peak of its maturity.

This time, I would like to talk about these two movements, comparing them from an engineer's point of view! Please enjoy until the end!

Comparison of "Cal.31 series" and "Cal.32 series"

As you all probably know, the "Cal.31 series" and "Cal.32 series" are both excellent movements, including the "Cal.3135" and "Cal.3255," both of which are considered masterpieces. We have covered this topic in other articles, so this time we will skip the basic specs and features and focus on their "weaknesses," which are not often discussed in general.

Weaknesses of the "Cal.31 series"

The "Cal.31 series" is often talked about as a masterpiece, but it has a few weaknesses. In rare cases, the crown may not be able to be pulled out. This is because the teeth of the gears inside the watch collide when the crown is pulled out.

Usually, if the crown gets stuck, you can pull it back in and it will work normally again, but the structure of this part of the "Cal.31 series" is somewhat complicated, and there are times when the problem does not improve no matter how many times you pull the crown back. When this happens, you will need to disassemble the watch and adjust it, which is probably its only weakness.

By the way, we would like to add that the problem of the crown becoming unable to be pulled out almost never occurs with the Cal.3130, Cal.3131, and Cal.3132 movements used in non-date models.

Weaknesses of the "Cal.32 Series"

In response to the weaknesses of the previous "Cal.31 series," the structure around the crown has been changed in the "Cal.32 series," and the symptom of being unable to pull out the crown has been almost completely eliminated. This is something you would expect from Rolex. Other improvements include an increased power reserve from approximately 48 hours to approximately 70 hours, and the adoption of a new ball bearing in the rotor of the automatic winding mechanism. If you only heard this story, you would think that the "Cal.32 series" was the clear winner, but in fact it does have some weaknesses.

This means that delays are likely to occur.

Rolex watches are famous for their extremely high accuracy, and currently, only watches that pass strict inspections that meet their own high-accuracy chronometer standards and have a daily accuracy of within ±2 seconds in the casing are shipped. However, when you push for such accuracy, even the smallest of things can have a big impact, leading to a delay of several seconds.

To go into more detail, it is believed that the reason for this is that not only has there been less play (gaps) between parts due to improved design and manufacturing precision, but the application of a coating process to prevent oil from splashing has further reduced play, resulting in increased frictional resistance between the parts.

This is a very small difference, about a few hundredths of a millimeter, but it still affects the operation, and I am once again amazed at the delicacy of mechanical watches. However, as expected from Rolex, with daily improvements, I personally feel that the frequency of delays in the "Cal.32 series" has decreased compared to before.

Conclusion

The "Cal.31 series" has a weakness in the "crown", which is a relatively infrequently used part of an automatic watch, while the "Cal.32 series" is at a slight disadvantage in that it has concerns about "precision", which is the most important point for a watch.

If you aim for high accuracy and eliminate too much play, it can lead to malfunction... It's the same for mechanical watches and people. (laughs)

*This is purely a personal opinion.

summary

This time, I thought about it again in order to compare the "Cal.31 series" and the "Cal.32 series," and I found that both are extremely excellent movements, with only minor weaknesses that could be "stated" as being weak points.

Also, although I may have caused some anxiety by telling you about each of the weaknesses, I want to be honest with you, and these are not at all frequent occurrences and can be sufficiently improved through maintenance, so please rest assured.

I hope this article has been useful to you and has piqued your interest in luxury watches!

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