Dr. Ito's thorough analysis of mechanical watches!! Vol.32 ~ About screw-down crowns and pushers

Good evening everyone!

This column talks about mechanical watches from an engineer's point of view. This is the 32nd installment.

About screw-down crowns and pushers

I will talk about this topic.

Humidity and moisture are the biggest enemies of mechanical watch movements. They can directly lead to malfunctions of the internal components, so they must be avoided at all costs.

To counter this greatest enemy, many waterproof watches, including Rolex, use "screw-down" crowns and pushers.

In this article, we will explain the structure and precautions for use of the screw-down crown and pushers, which are important parts for maintaining the water resistance of a watch, as well as some points that are likely to be misunderstood.

What is a screw-down crown?

The "screw-down crown" was adopted as a key element when Rolex developed the world's first completely waterproof wristwatch, the "Oyster," in 1926.

A normal crown can be operated as is, but a screw-down crown is designed to screw itself into the case, which provides a strong barrier against water and dust getting in through the crown. Therefore, you must unscrew the crown before operating it.

Rolex uses two types of crown mechanisms depending on the application and model.

One of them is the "Twinlock." It is mainly used on the Datejust and Explorer, and is characterized by a smaller crown diameter.

The other is "Tripock", which is mainly used in professional models with high water resistance such as the Submariner and Sea-Dweller.

It features a large crown and three dots under the crown mark.

The structural difference between Twinlock and Triplock is that Twinlock maintains its waterproofness with two gaskets, while Triplock uses three (currently four) gaskets.

Twin lock provides sufficient waterproof performance, but if you need to withstand higher water pressure, Triplock is a more reliable option.

By the way, non-screw-down crowns usually have a single gasket to prevent water and dust from entering. They are called "single lock crowns."

Even if you forget to tighten the screw-down crown, the gasket in one place will still function, just like with the single lock, so the watch is not non-waterproof and water or dust will not immediately get inside.

What is a screw-in pusher?

A screw-down pusher is a mechanism that prevents accidental operation of the chronograph by turning and tightening the button, thereby improving water resistance.

Rolex adopted screw-down pushers for the first time in a wristwatch, the manual-winding Daytona, Ref. 6240.

All Daytonas since the final model of the manual-winding Daytona, "Ref. 6263/6265," are equipped with this screw-down pusher and have the word "OYSTER" written on the dial.

What I would like everyone to know here is the difference in structure between a screw-down crown and a screw-down pusher.

The crown is designed to become more airtight when screwed in, but in fact, the pushers do not have a gasket on the screwed-in part, so their airtightness does not change before or after they are screwed in. So why are they screwed in? It is to prevent accidental operation underwater.

With pushers that are not screwed in, if you accidentally touch the push button underwater, the water pressure will cause water to seep into the case. To prevent this, the push button cannot be pressed unless the screw-in lock is released.

I believe that many people misunderstand this point, so I would like to take this opportunity to remind you of it.

Therefore, there is no need to tighten the screw-in pusher with too much force; it is sufficient to screw it in lightly until it stops.

summary

What did you think?

During this rainy season, I'm sure many of you are concerned about the water resistance of your favorite watches, so I decided to talk about crowns and pushers.

Don't worry, as long as you understand how to use your luxury watch and perform regular maintenance, you can still use it to the fullest even during the rainy season.

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 contact us directly and we will answer them thoroughly. We look forward to your visit and inquiries.

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