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Good evening everyone!
This column talks about mechanical watches from an engineer's perspective. This is the 42nd installment.
"What is 'under-winding' in an automatic watch?"
I will be talking about this topic here.
Many people who are using an automatic watch for the first time complain that their watch is running two or three minutes slower than expected, or that it stops even though it is on their wrist or set on a winder. We often receive inquiries from people who have just purchased their watch and are still within the warranty period, encountering such problems.
Some people may become worried and wonder, "Is this a defective product?", but in many cases the cause is that the mainspring was not wound properly .
When you hear the term "automatic winding," some people mistakenly believe that the mainspring will be wound automatically when you wear it on your wrist.
In this article, I would like to explain some common problems that occur with automatic watches.
What is insufficient winding?
"Underwinding" an automatic watch literally means that the mainspring is not fully wound, which mainly causes problems such as the watch stopping immediately or running slow .
However, while you probably have some idea of why a clock stops, why does it slow down? The mechanism has a lot to do with this.
For example, we all get anxious when our smartphone battery is running low. However, in the case of digital devices, computers are designed to control the battery so that it can be used normally until 1% is left.
However, analog devices such as mechanical watches can exert a large difference in power when the mainspring is fully wound compared to when it is starting to unwind.
As the mainspring unwinds, the torque weakens, making it harder to maintain consistent accuracy. This causes the watch to lose speed. If the watch is not wound enough, it will stop sooner than the actual power reserve.
So why does insufficient winding occur? It can be worrying when an automatic watch stops even when you're wearing it.
Even if you wear an automatic watch, if you do not move your arm much or wear it for a short time, the mainspring will not be wound properly.
Watch manufacturing technology has improved in recent years, and winding efficiency has increased significantly. However, wearing a watch for around eight hours a day is generally considered the best guideline for stable accuracy. If you only wear your watch to work and take it off at work, or if you mostly do desk work and don't move around much, it may not be winding properly.
Of course, there is also the possibility of malfunction.
Common problems include the oil running out in the automatic winding mechanism, causing the rotor to become slow to wind, or foreign objects such as dust getting in, or the screws becoming loose, causing the watch to lose its original winding efficiency.
Why automatic watches still need to be wound manually
If you haven't worn your watch for very long periods of time, or if your watch starts to lose speed or stop quickly, try winding the mainspring using the crown . Most mechanical watches require about 40 to 60 turns of the crown by hand to fully wind the mainspring.
When starting to use the watch after it has stopped, we recommend winding it by hand about halfway (20 to 30 times) before wearing it.
The important thing to be careful about is not to wrap it too tightly, and not to wrap it too much.
Manually wound watches always have a stop on the mainspring, but automatic watches use a rotor to wind the watch, so if there is a stop, the spring will be subjected to stress even when it is fully wound, causing it to break. This is a major reason why manual watches are said not to be over-wound.
For this reason, mainsprings for automatic watches are equipped with a " slipping attachment ."
As shown in the image above, the tip of the spring is forked so that even when it is fully wound, it does not stop, but rather slips, preventing the spring from breaking. For this reason, when an automatic watch is wound up more than a certain number of times, you may hear a slight sound of the spring slipping.
However, it is not a good idea to repeatedly wind the watch. Doing so frequently will put stress on the slip, causing it to deteriorate faster. As mentioned above, you should only gently wind the watch 20 to 30 times each time you use it.
summary
What did you think?
If you're having trouble with things like, "Huh? The time seems to be slow..." or "The watch keeps stopping...", please try gently winding the watch yourself using the crown before using it.
However, if you notice anything strange, such as "the accuracy is affected even though I am winding the watch with the crown," "there is an unusual noise that wasn't there before," or "the winding of the crown feels strange," we recommend that you consult the retailer where you purchased the watch.
We hope that this article has been useful to you and has sparked even a little interest in luxury watches! If you have any questions, please feel free to ask us directly and we will be happy to answer them. We look forward to your visit and inquiries.
Please look forward to the next one!
