Wavy Circles
We will now return to the dial plate that was set up in the last section for the trim line around the edge.
Cutting the first wavy circle around the dial plate, just inside the plain circular outer trim line.
The touch is now engaged with the rosette. The touch remains stationary and the rosette rotates with the workpiece, controlling the rocking motion of the headstock that generates the wavy circle on the workpiece. The headstock is sprung towards the touch by a large leaf spring at the back of the machine.
A small ladies fob watch about 20mm across with circles and fine concentric waves. (Yes I know the dial looks crooked but I assure you it is straight! I made it myself when I was at college and have it in my hand as I write this!) The use of enamel on the case over the concentric waves adds a rich colour to the design. The enamelled area has been neatly recessed before engine turning.
The Crossing Plate
By rotating the rosette barrel relative to the workpiece the pattern can be made to spiral. Progressing up and down this row of teeth produces...
... a circular zig zag pattern.
Many variations are possible using either the crossing plate or the work wheel to rotate the rosette barrel relative to the workpiece in different ways.
In this example on a cuff link with a central cabochon sapphire, a series of stepped progressions have been used, returning after the short spiral section to the original position and missing out the return of the zig zag to leave small spaces.