What's so great about Rolex's Oyster case? / Spring Wisdom - Answering your watch questions

Q: What's so great about the Rolex Oyster case?

The waterproof case of a Rolex, named after the Oyster, is what makes it so great? The foresight to introduce the screw-down crown and case in the 1920s and the advanced technology that made it possible are testaments to the greatness of the Rolex brand.

A: Pioneer watches that use screw-down case backs and crowns to achieve high water resistance.

A major feature of Rolex is its highly waterproof Oyster case. Named after the oyster, this case had a high level of performance thanks to its screw-down case back and screw-down crown. Of course, such waterproof cases are now commonplace. However, in the 1920s, only Rolex was able to use this case. It wasn't until the 60s, when the waterproof gaskets used in cases improved, that other manufacturers were able to make highly waterproof cases.

Currently, the monoblock middle case provides even higher performance.

The current Oyster case has evolved even further. The biggest difference from the previous model is that the inner case that held the movement in place has been eliminated. This is what Rolex calls the "monobloc middle case." In other words, current models using the Oyster case basically have the movement fixed directly to the case.

As a result, the case became stronger and, in theory, more water-resistant. However, directly attaching the movement to the case required machining with a high degree of precision. With today's machine tools, machining with high precision is possible. However, Rolex was the only manufacturer that could do this in the 60s, and even today, Rolex is the only manufacturer that can mass-produce hundreds of thousands of units.