Engine-turning (guilloché) process consists of engraving regular and repeated patterns using a specific lathe called a guilloché machine. It is a decoration found mainly on dials and sometimes on watch cases.

Its most prestigious version is made on a guilloche machine, a machine that is often more than a hundred years old, activated by the hand of man. It is an engraving made of straight and curved lines that cross and intertwine.

A more common quality version can be created with a coining machine. This will not, however, have the brilliance of a decoration made directly on a guilloche machine where the work is often much more time consuming.