Since the advent of mechanical watchmaking, talented watchmakers have transformed exquisite timepieces from ideas into reality with their dexterous hands. In addition to the intricate time mechanism, the manufacturer’s relentless pursuit of perfection is the hallmark of Haute Horlogerie. According to the concept of fine watchmaking, watchmakers use different techniques to retouch the movement.
The term ‘Finish’ covers a series of technical treatments of timepiece parts from production to the finished product. In the end, all processing marks were erased, and various parts were carefully polished and decorated by hand. The raw material becomes a work of art, which is called watchmaking alchemy.
A. Lange & Söhne Datograph Up / Down watch is equipped with a sophisticated movement L951.6. As always, the movement can be clearly identified by unique details. Its technical features and retouching include gold sleeves and blue steel screws.
In some cases, retouching may be useful. In addition to aesthetic considerations, the coating prevents corrosion. Geneva pattern can capture dust and protect the movement mechanism. Heating steel screws not only makes them dark blue, but also makes them harder in texture. In any case, retouching symbolizes the meticulous attention to small details when making the movement, which is also a strong guarantee for achieving perfect technicality.
Superb movement created by Finnish independent watchmaker Kari Voutilainen. At first glance, this movement is unpretentious, but in all aspects it reflects extraordinary craftsmanship. The flawless luster of a single balance wheel plywood requires hours of patient polishing.
Although modern CNC machine tools have also been used to produce and ‘roughly finish’ timepiece parts, carefully crafted movements are another matter, the latter can be considered real works of art. On the one hand, it is a programmed, high-volume industrial retouching; on the other hand, it has been passed down from generation to generation, and the skilled craftsmen add charm to the parts little by little, stroke by stroke. The two are different. Some operations, such as the handling of specific angles (inner or sharp corners), can only be done manually. Finally, hand retouching makes each piece unique, and ‘imperfect’ instead becomes the most authentic gift. You know, even trained watchmakers can’t make two identical works.
Chamfering (Anglage / Bevelling / Chamfering)
Chamfer of Audemars Piguet movement bridge.
Chamfering involves treating the edges of the part to the same angle (usually 45 °) and width, and is generally used for bridge and floor finishing. Carefully polished edges accentuate the shape of the part. The chamfer must be neat and smooth. This is one of the finest retouching techniques.
Use grinding tools to chamfer the movement bridge.
Nowadays, machines can shape sharp-cut chamfers, which not only makes industrialized large-scale retouching possible, but also makes the second stage of work in high-end manufacturing easy. Watchmakers can manually control the machine tool, guide parts and tools, and further Optimize chamfers.
The file is used to manually chamfer the Vacheron Constantin skeleton movement, and the finishing of complex shaped parts can only be done by hand.
Manual chamfering with traditional tools such as files, dowels, and abrasive slurries is unmatched by modern machining and is still essential in the internal processing of parts. Different abrasive pulps have different degrees of fineness and can be used continuously to obtain a flawless gloss. This project requires dexterous hands and superb skills. There is a type of angle that can only be done by hand, that is, rounded corners. It is regarded by the industry as the holy grail of fine watch finishing, and Romain Gauthier and Philippe Dufour are exemplary models. The rounded surface is not flat, but convex, and only a very small number of highly trained watchmakers can achieve this level of detail.
Black / Mirror Polish
Black polishing, also known as mirror polishing, is a very time-consuming retouching process and a major feature in fine watchmaking. This process is used to obtain a perfectly smooth surface of a steel part, making its surface glow like a mirror, and staring at black from a specific angle. Black / mirror polishing requires a completely flat surface, no irregularities (the edges of the part must also be completely flat), and the reflection of light must be in the same direction. Depending on the light, the reflection can appear black (when the light is perpendicular to the part), metallic gray, or white. Black / mirror polishing can reduce the risk of oxidation, but of course it is mainly used as a decoration.
Movement parts before and after black polishing (left); gentle polishing of movement parts for mirror polishing (right).
In order to achieve this effect, the surface of the part must first be regular and flat. The rougher the surface, the more dull the surface. After the formation is flat, wipe the surface of the part against the zinc plate. With diamond abrasive pastes (these pastes will become thinner and thinner until the process is complete), the watchmaker will make circular movements of the part to remove surface imperfections until a perfect black / mirror finish is achieved. This process is very time consuming and is usually only used for high-end watchmaking. For example, only black / mirror polishing of the top surface of the tourbillon splint can take up to 3 hours.
The use of a rotating abrasive to remove excess metal creates parallel lines that form a Geneva pattern, a part of a Christophe Claret movement.
The Geneva pattern is one of the most traditional retouching types, and usually refers to the regular, parallel wavy pattern on the surface of the movement parts (such as the floor, bridge and oscillating weight). The Geneva pattern can also be straight or round and perfectly aligned across different parts.
Laurent Ferrier tourbillon watch, striking ribbing across the bridge.
This retouching is mainly applied to the flat and visible part of the bridge (the bottom plate usually uses fish scales). The decoration of the Geneva pattern can have a variety of techniques, the most commonly used being semi-automatic machines guided by human hands. The parts are fixed on a moving tray, and the surface of the parts is scraped by means of a grinding tool. A more modern (and even more affordable) technology is the use of CNC machine tools without the need for human labor. Finally, there are all manual solutions, which are very time consuming and less regular, but look more beautiful. Need to use wooden grinding tools to mark the parts with the same distance, size and style.
Fish scale (Perlage / Circular-graining / Stippling)
Fish scale decoration on bridge or bottom plate (left); movement parts undergoing fish scale decoration (right).
Fish scale pattern is another traditional retouching process, also known as rotary circular pattern or stippling. It refers to the use of rotating wooden nails to decorate overlapping small circle patterns on the bottom plate or bridge surface. Such patterns are often found on hidden surfaces, such as the back of the floor (under the dial) or recesses. This is one of the few processes that cannot be fully automated and usually requires manual work.
Engraving movements are usually used to display brand logos or various information. This process can also be used to personalize the parts and make them real works of art.
Vacheron Constantin’s movement bridges are hand-carved, wax bridges are used to fix the bridges, and simple traditional tools and superb craftsmanship are used. The finest part of the bridge is only about one-fifth of a millimeter and is not pre-designed.
There are several ways to engrave the movement. Large-scale production, usually using CNC machine tools, lasers or chemicals. Hand engraving is an extremely complex, time-consuming and delicate process. Hand-carved parts will make people feel very different. Under the microscope, you will find rough lines and subtle flaws, which also adds a unique luster to it.
Philippe Dufour Simplicity watch movement with flawless Geneva prints, chamfers and finishes. Philippe Dufour is one of the most respected and talented independent watchmakers in the fine watchmaking industry and is highly regarded by connoisseurs for his uncompromising pursuit of perfect hand-made watchmaking.
This is a process of engraving and polishing the concave surface around a screw head or gem. Drill holes in advance, and irregular edges of the holes can be polished by hand.
Even the smallest parts, such as screws, must be beautifully polished to add brilliance to the movement. Screws are usually polished and burnt blue, the latter is a traditional process with attractive colors.
GP Girard Perregaux Esmeralda tourbillon watch, the three gold bridges are fixed with very small screws.
Today, some brands choose to switch to process polishing or chemical blue technology, but high-end manufacturers still insist on inheriting the century-old skills. Using a polishing agent, patiently rub the screw head, polish it, and burn it blue. During the blue burning process, the screws must be heated at a very precise temperature to obtain the proper and the same color.
A. Lange & Söhne movement, polished blue steel screws, holding the gold sleeve.
In high-end watches, especially those with the Geneva Seal, the gears are often retouched to carefully remove processing marks.
The Patek Philippe 5016R Tourbillon Minute Repeater watch, the curved spokes on the gears are completely decorated by hand chamfering.
The upper and lower sides of the gear spokes are chamfered, the concave surface is polished, and the surface is rounded with satin. Pinion ridges and other moving parts are polished while ensuring that these operations do not affect their functional shape.