Hand finishing is the last stage of making a watch movement, when a watchmaker treats the parts by hand, for looks and for function. It shows off the maker’s skill. It can also add a lot to the price: in one Geneva Seal movement, the extra hand finishing made it 50% more expensive.
What is anglage?
Anglage is a central hand-finishing technique. The finisher files the sharp edges of bridges and plates into a bevel, then polishes it. The bevel keeps the same angle all the way round, usually 45 degrees. The traditional tools are metal files, or wooden pegs charged with abrasive diamond paste. The finisher works through finer and finer grades of paste, much like sandpaper, until the surface has a mirror polish. The work is slow and needs a lot of dexterity. One slip can ruin the whole part.
How is hand finishing different from machine finishing?
Modern machining lets brands skip much of the hand work. Machines can cut the first bevels on many parts in large volumes. But a machine cannot finish the internal cut-outs of a skeletonised part the way a watchmaker can. Some decorations can be done either way. Perlage, or circular graining, can be applied by hand or by machine. It is typically used to remove the traces that machining leaves on the surfaces of parts.
What other finishing techniques are there?
To make a very flat, polished top surface by hand, the finisher moves the part in a figure-eight pattern over abrasive paste. Geneva stripes are another finishing pattern. They were traditionally said to trap dust and keep it away from the more delicate parts of the movement. So finishing is not only about looks. Some treatments were also meant to do a job.
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