SAVOIR FAIRE Swiss-made Savoir Faire, Chapter Five: The art of assembly

This week, we’re taking you inside our home, the TAG Heuer factory in La Chaux-de-Fonds. It’s the perfect place to continue our exploration of our legendary savoir faire. 

La Chaux-de-Fonds is an UNESCO World Heritage site, and it only takes a few minutes of being there to understand why. With its orderly matrix of wide streets and stucco townhouses, this town feels like an homage to watchmaking. Make your way to Rue Louis J. Chevrolet and you’ll see an off-white three-storey building with a tall facade that reads TAG Heuer: Swiss avant-garde since 1860. This is the TAG Heuer factory. All the different watch parts are delivered here for assembly. Remember the cases, the dials and the movements from our manufactures in Cornol, ArteCad and Chevenez? Well, this is where they come together.

Enter the building, walk past the TAG Heuer museum and you’ll be led to the place where all the magic happens. The wide, spacious assemblage floor has a peaceful, zen vibe to it. Sunlight pours in through the large glass windows. The expert watchmakers sit on their stools, with long-armed table lamps just above their heads. Everyone here is working away meticulously. Around 40 watchmakers take up this space. They’re not just highly-skilled; they’re multi-skilled. So they can easily swap jobs and keep things ticking. There are screens that display everyone’s plans for the day, so they can know what needs to be produced by when. Most assemblers work silently with their eyeglasses on. Others exchange notes. Some are studying blueprints on their computers, to make sure they’ve got the intricate details of their timepiece right. Everything is moving like clockwork.

It takes years of learning and refinement to master the art of assemblage. You need a keen eye, steady hands, and an immaculate understanding of everything that goes into the watchmaking process. You can see this know-how coming to life on the assembly floor. It all starts with the watchmakers carefully working on the dial. You need delicate touches, and a vacuum or a pin, to set the hands and turn the stems to the correct position. Then a ring is used to fix the dial to the movement. The partition between the hands needs to be perfect, so the watchmakers are assisted by a machine that helps control the pressure. First you set the hour hand, then the minute hand, and finally, the seconds hand. The spaces between the hands, and the position of the hands, need to be controlled and leveled. The machine lights up to tell the watchmaker when there’s too much or too little pressure. The green light indicates that the pressure is right, and the red light suggests it isn’t.

Next up, emboîtage, which means “casing”. The watchmakers place the perfectly-made dials into cases and secure the movement. They test all the functions, like the date changes for example. Airflow is tested using overhead vents that push out air, to avoid dust. It’s quite engrossing to watch the little details these experts get into. In between every process, there are quality checks. Check the oscillating weight, compare the metric of the movement from when it was at its manufacture to now. Insert the case ring, create the link between the middle case and the movement. Test the power reserve, the functional reserve and voila, the assembled piece is off for further testing.

After the assembled pieces pass the watchmakers’ test, they go into an adjacent room for further examination. This room contains many different watches carefully set in vats, with tiny molds for every piece. These vats are slowly lowered into special containers. You can regulate these containers to various pressures. So every piece can be tested to make sure they’re water resistant and air proof. Depending on the specifications of each watch, the container is set to lower or higher pressures. You start at a lower pressure and keep increasing it until you reach the watches’ designed pressure point. After this, the pieces are placed on a warm plate to simulate humidity. Each watch is anointed with a drop of water to make sure there isn’t any condensation. One final quality check later, the watch cases are all set to go to another atelier, so they can be fitted with bracelets or straps.

There you go, the art of assembly, straight from the TAG Heuer factory.