Skimming the part to the correct diameter. Note the trimmed-off waste to the left of the cutting tool.
Before removing the finished trim from the convex tool, it is placed in the chuck and polished under power using very fine emery cloth and metal pollish. Alternatively, if a 'spun' satin finish is required, then fine or medium emery paper can be used, omitting the metal polish.
After removal, the inside of the trim is cleaned and roughened with coarse emery paper to provide a 'key' for the adhesive. The completed knob-bright is then coated with Rustins Clear Metal Lacquer in order to preserve the shine and prevent tarnishing.
Finished bright fixed to knobs with urethane adhesive.
Although not quite of production quality I am pleased with the result, and I will certainly use the method again. The shallow concave dome stye favoured by Grundig and Philips may prove more challenging, and would certainly require a special spherical cutting attachment to make the tools.
Edward