how a french horn is made
The French horn is made up of 13 feet of coiled tubing, a set of valves, and a flared bell. To make the tail end, they shape a sheet of brass around a still mandrel. Then they braise the edges together to form a tube. With a burnishing tool an artisan rounds out the shape. Next, they lubricate a brass disk as it spins on a lathe. Using a variety of tools they shape it into a bell. A plasma weld machine then fuses the bell and the tail together. Back on the lathe they trim the diameter of the bell then roll the edge into a rim called a bead; this reinforces the bell. Next they fill the bell with a hot tar like liquid called pitch. Once the pitch cools they put the tail into a forming block and carefully bend it. The hard pitch provides support preventing the tail from collapsing. They verified the band against a template. Using the same technique they shape the pieces that form the horns tubing. Of all the brass instruments the French horn has the most complex bends. Valve knuckles connect the tubes to the cases that will house the valves. Some French horns have three valves and double French horns have four. Each valve case goes on to this alignment device, which pushes in the knuckles to the correct depth. After brazing the knuckles to the cases they hollow out the case interiors with a cutter. Then they solder the valve cases to each other with connecting rings. They insert the tubing parts into the valve knuckles. There are curved tubes called slides. The musician tunes the instrument by adjusting them in and out of the strait tubes. After soldering the straight to the knuckles they remove the slides for now to make other areas accessible. Then they solder a partially assembled valve section to the tail and bell. Now they apply buffing compound and polish the horn’s interior surfaces they polish the more accessible services with the cloth buffing wheel. Then they wash off the compound and coat the entire surface with a protective lacquer. Now final assembly of the valve section can begin. They install rotors in the valve cases and levers to activate them. Unlike piston valves on the trumpet that move up and down these valves rotate to direct airflow through specific tubing combinations. A lever connects to each valve via a rod and nylon cord. With the valves section now complete the reinstall the slides then do a final wipe down to remove grease residue and fingerprints. Its pristine finish compliments the superb sound quality.