Stamped and ground
How do you recognize a high-quality watch case? Quality of production, but also of finishing. We show the decisive steps in text, photos and a video: Put in the right shape, worry polishing, satining, finishing or hardening for the perfect appearance.
The path from raw metal to watch, which clings to the wrist, is long and arduous. At the beginning there are long metal strips, strips or blocks from which the basic shapes are punched out. The tools for this are made extra for each housing shape and size.
From the blank to the watch case
Whether round, angular or curved is already apparent after the first work step, yet the stamped blank with the finished watch case has no more than the shape in common. Especially in the case of complex dimensions such as a Tonneau housing, after the first punching, further, partly very elaborate punches follow. Even with a housing floor alone, it can be up to ten or 15 in number before this is ergonomically completed.
The blank is also brought into shape by embossing, turning or milling. To solve the resulting internal stress, it must be treated heat after each of these processes by heating the metal to over 1,000 degrees. The casing parts must also be washed after each work step and deburred after each punching process. The latter takes place in a drum with abrasive stones, which rub off the edges. The milling is done on modern CNC machines with high precision. The tool automatically rotates around the housing and gives it the desired shapes. If the target is a particularly high-quality watch, you are already striving for a smooth surface when milling, as this facilitates the final surface treatment.
The holes for the spring and the Crown must also be installed exactly, which is also done automatically. Together with the holes for the housing floor screws, the internal thread is cut if necessary. A CNC machine operates on five axes and requires five to twelve minutes per housing part. When the contours of the housing are completed, the surface is embellished.
Not to be underestimated: the final machining of the watch case
Depending on the material–whether gold or platinum, titanium or stainless steel–the sequence of work steps, the tools used and the working time spent are different. Overall, the surface finish is much more complex than expected: depending on the geometry and material, it can be time-consuming and expensive.
The polisher is responsible for the good looks–in Germany, a training occupation with two to three years of teaching time. In Switzerland too, the Polisseuse–formerly the surface treatment of typical women’s work–or the Polisseur had to learn two years to perfect the finishing of jewellery, watch or ribbons. Their knowledge includes not only the mastery of all the operations of polishing, satining to matting, but also the knowledge of galvanic finishes. With a great sense of touch, the polisher removes the last traces of the work and gives the metals a radiant appearance.
At the beginning there are extensive pre-treatments: first coarse, then always finely honed. For titanium and stainless steel, the pregrinding is done on round grinding wheels or on belt grinding machines with the addition of oils. Such lubricants are important for surface treatment: Pastes or liquids are also used for Lapidierening or polishing. For example, Diamantine, a powder of pure annealed clay for polishing steel, Polierrot (also called Rouge or Parisian red) made of iron oxide for the processing of gold alloys or polished green from oxide for polishing platinum and white gold.
More information about Titanium Watch cases can be found here.
And here you will find more about stainless steel casings.
In the video: How Jaeger-LeCoultre manufactures the Reverso housing
Stéphane Belmont, Directeur Marketing & Création Jaeger-LeCoultre, and watch expert Jeff Kingston show in the English-language video How the Reverso enclosure is created. Find out here what makes the production of the Reverso enclosure so demanding:
If you want to learn more about making the finest watches, follow our YouTube channel IBG worldwide. IBG Worldwide is a video platform demonstrating the production and operation of sophisticated mechanical watches from JiBin123 with impressive impressions from the manufactories.
Chemicals, brushes, sand: A watch case must withstand a lot
These lubricants are becoming more and more fine from operation to operation. On two to three fine grinding processes–This includes the felting on a disc with a textile structure as well as the fine Lapidieren on a hard, metal disc–follows the surface treatment, which finally gives the housing the final face: polishing, Brushing, matting or sandblasting. The Polish gives the metal mirror-like shine and is done on polishing motors equipped with brush, felt and wool discs. The craftsman presses the workpiece against these rotating discs. For low-cost mass production, there are automatic scrubbing or polishing drums as well as electrolytic polishing. In contrast to the shiny, polished surface, a matt watch shimmers velvety and textureless. This optics is created by a multitude of finest notches, which are produced, among other things, by sandblasting, pickling, grinding or brushing.
The sand or sphere rays are carried out in a hermetically sealed cabin. During manual processing, the workpiece is kept in this cabin by hand – naturally with protective clothing, where the finest sand or tiny glass beads are blown up with high pressure. Another option is to insert the workpiece into the cab in a rotatable basket. The fine ball radiation is very complex because it can only be made on perfectly polished surfaces. The satining is also laborious. This term refers to a very fine stripe cut on watch, which gives a matt silky sheen. This process owes its name to the said gloss, reminiscent of the satin fabric.
Material and construction decide on the cost of housing production
Of course, the material also influences the finishing effort: Platinum is stubborn and tough, while gold can be easily processed. If a gold casing is processed with diamond tools when turning and milling, a very smooth, shiny surface is already created. For simple gold enclosures A simple polishing is sufficient. However, the construction of the housing is crucial for the cost of surface processing. The more complex, the more layers, edges or corners, the more elaborate the finish. Then, work steps that take only a few minutes to complete will take considerably more time. Sometimes even the construction of new polishing machines is required. The combination of mat and polished surfaces can only be done manually and requires a lot of time and work. In certain models, the finishing of the housing also includes the finishing of the electroplating. This causes a coating of gold or rhodium to be applied. By means of electrolysis, precious metal is deposited on the housing in baths. At the Rhodinieren a sister metal of platinum is used: Rhodium. It is hard and sturdy, oxidized not and shines in pure white. Therefore, it is often used to give white gold a shiny finish. However, this is not necessary for expensive white alloys with high palladium content–it radiates by itself in perfect white and is completed by polishing, matting or satining.
In the case of gold, the galvanic coating is referred to as Plaqué; The thickness of the gold plating is given in microns–one micron corresponds to a thousandth of a millimeter. In contrast, the gold is gilded by welding and rolling. An alternative is the technique PVD (physical Vapour deposition). A metal base is coated with gold-colored titanium and covered with a golden layer. This is done in a vacuum either by cathode atomisation or evaporation or by evaporation of high-intensity plasma radiation (Ionplating). The result is even, glamorous and resistant.
Learn more about the manufacture and properties of platinum enclosures here.
More than Beautiful: What use can the watch case finish have
Keyword resistant: For some manufacturers the hardening of stainless steel is also one of the watch to make it scratch resistant. The material is first heated to a certain temperature and then cooled at such a rate that a significant increase in hardness occurs superficially or thoroughly. In today’s watchmaking industry, modern technology and traditional craftsmanship combine to Trefflichste.
Tags: carbon watch, German watch manufacturer, stainless steel watches, gold watch, Jaeger-LeCoultre, Jaeger-LeCoultre Reverso, Platinum Watch, Swiss watches, Titan Watch