The gasket system used by Rolex to seal their sapphire crystal (the “glass” that protects the dial and hands) to the watch’s case, is one of the best in the industry. I have yet to encounter a better engineered, more reliable, or impermeable system than the one they employ on their Oyster cases.
In an average watch, the crystal is held in place with a simple, nylon ring. This ring, which we call a gasket, is typically left exposed to the elements, including direct exposure to UV rays, and serves up a straight passage for moisture to enter the watch should it ever fail.
In the case of a Rolex Oyster, this gasket features a small hook-like ridge on its upper edge that fits securely into a channel cut in the perimeter of a Rolex sapphire crystal. Depending on the particular model of Rolex, this gasket may feature other small ridges or undulations, as well, all in the name of increased reliability in thwarting the ease with which liquid can penetrate the seal.
The ridge on the gasket that holds the crystal in place effectively doubles the the distance a liquid or gas must penetrate to enter the watch via the seal at the crystal and also serves to increase the width of the gasket’s frontline defense. Once the gasket and crystal are fitted together on the case, the gasket is fastened tightly to the case by a metal ring in such a way that also doubles the distance a liquid or gas must travel to penetrate the watch via the gasket’s outer edge. Another benefit of this system is that, once sealed, the gasket is protected from the elements by the case, crystal, and metal ring or bezel. Furthermore, because the gasket is under pressure on all sides, the gasket cannot become dislodged following a strong impact or change in pressure, as it can in a more traditional configuration where the upper edge of the gasket is exposed.
In light of these differences, this gasket configuration requires a different approach to installation compared to the majority of other watches on the market, which use the simpler nylon ring gasket. In most watches the gasket is typically installed into the case first and a case press is then used to press the crystal into place. However, in the case of a Rolex (or Tudor), the gasket must be installed into the groove in the crystal first and the crystal and gasket must be installed on the case together before a casing press is used.
Although it quickly becomes second nature once you’ve done it a few times, installing the gasket on a crystal before installing it on the case can be cumbersome. The following short video clip demonstrates a simplified approach I began using several years ago, whereby the crystal is fit into the gasket while on the case, and is the method I’ve found to be most expedient and failsafe. This is just one example and certainly not the only approach. Some of our readers are likely already familiar with it, but for those who aren’t it’s a timesaver I felt worth sharing.
If you have a different approach or other timesaver to share, let us know in the comments.