BEZEL
The bezel is to the dial what a frame is to a masterpiece painting. It defines the contour and concentrates light to focus one’s gaze. The shape of the bezel generally adapts to that of the case and knows no other limits than the designers’ creativity. Technically, the bezel encloses the upper part of the case and carries the crystal that overlooks the dial. The water resistance of gaskets between the middle part and the crystal is therefore crucial.
From the earliest pocket watches to the latest horological creations, the bezel has always been a preferred decorative element with gem setting, engraving, and enamelling. Over time, the bezel has become an information carrier. Its inner circumference (visible under the watch’s crystal) frequently features one or more graduations (hours, minutes, seconds, tachymetric scale, pulsometer, etc.). These graduations can be engraved, printed, or set (appliqués, stones, etc.). Seldom, the outer circumference of the bezel is engraved (e.g., hour markers) and sometimes lacquered.
The bezel can sometimes rotate. In such cases, the crystal is generally directly fixed to the middle part, with the bezel becoming a rotating ring. The most well-known application of this system is the unidirectional rotating bezel of dive watches. However, numerous specific applications exist.
By engraving an angular graduation on a rotating bezel, the watch becomes an excellent navigation tool. In other examples, the rotating bezel becomes a slide rule, whether general or specialized. In numbered cases, a bezel was used as a substitute for the crown. This allows the watch to be wound and set by rotating the bezel.
Starting in the 17th century, watch cases became more refined and technically advanced. The three-parts construction (middle part, bezel, & caseback) became widespread.
Like casebacks, bezels are often connected to the middle part by a hinge. The bezel can thus be opened with a tab and pivots on its hinge like a window. Later on, bezels would be soldered to the case or more commonly fixed with a notch (snap-on).
In modern constructions, it is often preferred to screw the bezel directly to the middle part. Generally, the screws engage beneath the middle part and tighten under the bezel. The caseback then covers the bezel screws, making them completely invisible (both on top and below) once the watch is closed.
In other cases, the screws engage from the top of the bezel, passing through it to tighten into the middle part. In this case, the screws are visible.
With the crystal it holds, the bezel is the component most exposed to impact. It’s not surprising that the bezel is often a testing ground for new materials (hardness, scratch resistance, UV resistance, grip, etc.). To the extent that some designers today conceive bezels as “shields” or shock absorbers protecting other elements of the case and movement.
Depending on its design or technical specifications (water resistance, function, etc.), producing a watch case’s bezel may require feats of ingenuity and craftsmanship. However, like the caseback, the bezel is often relatively simple to manufacture and does not need extensive resources. A bench lathe may suffice in many cases to manufacture a circular bezel, while a milling machine will be used to create bezels of various shapes (square, barrel, etc.). The amount of work required for such a method, but also the quality obtained, often leads watchmakers to decorate their bezels using traditional methods (engraving and/or hand setting, enamelling, etc.).
The manufacture of a bezel closely resembles that of casebacks. Therefore, as with the industrial method, machining centers (CNC) are already predominantly used for such production volumes. What mainly differentiates the two production methods are the finishing, decoration, and sometimes assembly stages for the most complex bezels.
For small series of watches at a certain price level, hand engraving is still often preferred over mechanical or chemical engraving. The placement of stones for setting is done by hand rather than by machine, as is the assembly of different components (e.g., the ceramic insert of a dive watch bezel).
On an industrial scale, bezels are mostly manufactured using machining centers (CNC). However, stamping can be preferred to machining, especially for non-circular bezels. In the latter case, machining operations are often necessary after stamping.
For the most complex bezels, the assembly of the various components may be carried out on assembly lines or even automated.
Once again, high-tech methods of production are distinguished from artisanal, semi-artisanal, and industrial ones primarily by the materials used rather than their production volumes. Injection moulding and sintering are predominantly employed to shape materials such as plastics, composites, and ceramics, even though standard machining and/or polishing operations may sometimes be required subsequently. The manufacturing process for sapphire cases and bezels (synthetic corundum and its derivatives), and therefore for watch crystals, resembles the industrial method (machining/polishing). However, the hardness of sapphire requires the use of high-tech machinery and tools.