The picture is of a rose engine machine. It can be used to decorate clock dials, watch housings, boxes and other round or oval objects. There are also rose engine machines that only engrave straight-line patterns, which are usually in the form of rectangles. Examples of that technique’s application include tie tacks, cigarette cases and lighters and ballpoint pens. Objects with convex surfaces like cups or even spheres can also be decorated using this technique.
The principle behind the guilloche technique is basically very simple: The workpiece is guided along a rigidly mounted burin in order to scribe one groove after the other into a surface. This technique is fundamentally different from standard engraving whereby it is the burin that moves freely and the workpiece that is rigidly mounted. The control of the workpiece is taken over by the mechanism of the machine. The depth of the engraved line is controlled by the guilloche engraver by means of the pressure he uses to press the tool and the workpiece against one another. Disc-shaped or rail-shaped templates that are attached to the rose predetermine the form of the pattern. The mechanism of the machine follows the patterns on the rose and transfers the design to the workpiece. In this way, the pattern designed by the “guillocheur”, which is made up of straight, waved or zig-zag lines, is scribed into the object surface one line at a time. With guilloche engraving, the line closeness can be set at the mechanism of the machine to assure a precise and orderly pattern. The range of possible settings for waves, angles and separation distances, and combinations thereof, is endless and, if nothing else, only limited by the imagination and skill of the operator.