Anglage is the French name watchmakers use for bevelling or chamfering: cutting a sloped edge of even angle and width, usually 45 degrees, mainly on bridges and plates. It started as a practical step and is now chiefly decoration. Done well, it shows the watchmaker’s skill, and it is required for the Geneva Seal.
How is anglage done?
The edge is cut into a slope that keeps the same angle and the same width from one end to the other. The angle is usually 45 degrees. The traditional hand method uses files, wooden pegs and abrasive pastes. Some bevels are made with an abrasive tool instead. Even then, the tool does not do the job alone: a skilled worker has to guide the part by hand. Patek Philippe counts anglage among the hardest finishing methods.
Why do watchmakers bevel edges?
Anglage began as a practical fix. A sharp edge on a bridge or plate could damage other parts of the movement, and it could trap dirt. Taking the edge off removed both problems. Over time the purpose shifted. The bevel became mainly decorative, and that is its role today. A clean, even chamfer is hard to make, so it shows the skill of the watchmaker who made it.
What does the Geneva Seal require?
The Geneva Seal sets firm rules for chamfering. The top edges of every plate and bridge in the movement must be chamfered and polished. Wheels must be chamfered on both sides, though wheels no thicker than 0.15 mm may be chamfered on one side only. The edges of strip springs and jumper springs must be chamfered all the way round. The rules do not say how the chamfer has to be made. An edge cut by machine and then polished by hand would therefore pass.
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