Engine-turn machine, or guilloche machine, is a machine that is often centuries old. It is used to make the guilloche decorations on the dials or watch cases.

It is always operated by human hands and therefore works without a motor. As with other machines, the sharpening of the chisel and the respect of the cutting angles is a big part of the work.

The heat treatments given to the chisel are also important. For dials, silver is often considered the best material for guilloche dials because of its hardness.

This decoration can also be made by striking. It is a simpler and faster way but purist customers prefer the decoration made with the guilloche machine, more laborious but more beautiful by its reflections. This is the reason why some brands maintain the old fashioned guilloche work on guilloche machines.