There are many steps to making a cylinder, the main ones are presented on this page.
Simply summarised, the process can be seen in the image below. Beginning with the rough brass cylinder, preparing the surface, drilling the holes, the first polishing of the brass, adding the pins, sealing them with resin from the inside, final assembly of the caps and drive spindle.
After the surface is prepared, two cylinders are placed together, joined by a steel collar and then drilled in preparation for the pins to be added. Whilst the drilling is being executed a technician continuously floods the drum with cutting oil applied by a brush to facilitate the machining to keep the holes as clean as possible whist being drilled.
The pins are made from piano wire, dispensed from a large roll and fed through the machine, pushed into the holes drilled in the previous step.
As each pin is positioned in the cylinder, it is then cut from the roll by the two tungsten circular cutters. The length of each pin remains longer than needed to be able to rectify all of the pins simultaneously to the same length and polished at a later step.
The two cylinders are connected by a steel collar. The holes are positioned differently for each melody and on the larger cylinders there are three melodies. Following the drilling of the holes the cylinders are removed from the machine, polished again and then returned to another machine (shown here) to place the pins. Requiring the indexing between machines to be exact so as to assure the drilling and pin positioning are perfectly aligned.
Once the pins have been inserted they protrude through the internal wall of the cylinder and are locked in place with a resin which is added to the inner cavity. The resin is rock-hard when cold and is melted to be injected into the cylinder.
The process is executed manually in a tailored workshop specifically for this process called ‘Gommage’.
The resin is placed in blocks into the heated steel pot on the left hand side and heated to 150 degrees centigrade to melt it into a liquid which will later be pumped into the cylinder.
As the resin is heated a vertical mixing rod mechanically plunges into the stainless steel pot mixing the resin into an even constituency. The resulting liquid is manually pumped.
The resin used to lock the pins in place. In its cold state it remains rock like in its consistency. The recipe remains a Reuge secret.
The steel supporting heads for the cylinder are coated with a heat resistant green grease to avoid the cylinder becoming glued between the heads when the resin is pumped inside.
The cylinder is then spun at a high speed powered by the electric motor on the right. As the resin is pumped inside, the surface is cooled by an air gun shooting cold air on the turning exterior surface of the cylinder.
When the cylinder is removed, the pins are locked by an inner wall of cold, hard resin. The centrifugal force of the turning cylinder assures the wall is even. The quantity of resin pumped inside is judged by the technician operating the hand pump.
The cylinders require a clear passage through the centre to allow the spindle to have access and pass through.
Nearly every step of the process of making the parts for the music boxes requires human interaction with the production, often using the same techniques that have been used for at least the last 50 years, on occasions as with the application of the resin since over 100 years.
A key-way is pushed into the resin whilst it remains hot.
The cylinder caps are locked in place by a combination of a double composite cement placed on the contact surfaces combined with a friction fit which is executed by a press.
The position of the caps in relation to the pins on the surface of the cylinder is specific. The pressing tool which closes the two caps in place incorporates a simple system that allows the technician to turn the drum on the caps, until the red light is activated. This indicates the caps and cylinder are correctly aligned, then the operator applies pressure to the press and squeezes the assembly together.
Once the cylinder is assembled it is placed into the machine below. Hidden under the red cover is a precision grinding stone which runs along the length of the cylinder, grinding the heads of the pins to a regular length and even finish.
At each manufacturing stage the cylinder is visually checked. Ensuring that all the pins are in place and the overall aesthetic of the piece is free of any scratches, or marks that the polishing process could not remove.
The final steps in the process are to polish the cylinder which is executed by placing it in a manually held jig which allows the cylinder to turn as it is buffed, using the polishing compounds applied with brushes. The buffing both finishes the surface of the brass and the steel pins. Following the polishing a protective layer is applied to the surface to prevent any future oxidisation, after which the spindle is inserted.
Finished cylinders with their spindles.
Two of the people involved in the process.
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