Polishing Wheel — The Buff That Carries Compound to Metal
Polishing Wheel — The Buff That Carries Compound to Metal
Layered cloth, felt, and leather wheels that take precious metal from cut to mirror
A polishing wheel, also called a buff, is the rotating disc mounted on a polishing-motor spindle that carries abrasive compound onto the surface of the work. The wheel itself is the substrate; the compound is the abrasive. Selecting the right wheel material for the stage of work and the metal being polished is as important as selecting the compound, and an experienced bench worker reaches for a different wheel for cut-down on a heavy casting than for the final mirror pass on a finished ring.
Construction and types
Stitched-muslin wheels are the bench standard, built from layered cotton cloth discs stitched together at one or more concentric circles, with the stitching radius determining the firmness of the working edge. Loose-leaf muslin wheels, with discs free at the rim, give a softer, more forgiving cut and are used for the final polish on rouge. Felt wheels, denser and harder, are used for harder alloys and for situations where the operator wants to preserve a sharp edge or a flat surface that a soft wheel would round over. Leather wheels, harder still, are reserved for hardened steel and for selected gemstone applications.
Wheels are also produced from chamois, treated wool, and synthetic fibres for specific applications. Diameters range from a small inch-and-a-half wheel for tight detail work on a flex-shaft handpiece to twelve inches and larger for production benches working heavy fabricated and cast pieces.
Loading and use
The wheel is mounted on a tapered arbor, which self-tightens in the running direction. With the wheel running, the operator touches a compound bar to the rim until the surface darkens and the binder transfers; the wheel is then ready to take the work. Compound is reloaded as the cut slows. A single wheel is dedicated to a single compound — a tripoli wheel never sees rouge, and vice versa — because cross-contamination at the final stage leaves visible scratches that have to be cut down and refinished.
Wheel selection by stage
Initial cut-down on a fabricated or cast piece is run on a stitched-muslin or felt wheel charged with tripoli, with the operator working systematically across the surface to remove file marks and emery scratches. Intermediate work, where required, is run on a slightly softer wheel charged with a finer compound, often white-diamond compound for gold or chromium oxide for harder alloys. Final mirror polish is run on a loose-leaf muslin or chamois wheel charged with rouge, with the operator working with a light touch and watching for the moment the surface comes alive.
In the trade
A working bench keeps a labelled rack of wheels in graded sizes and materials, each dedicated to a single compound. New wheels are broken in by running them against a piece of scrap until the rim is true, and they are dressed periodically with a wheel rake to remove glazed compound and expose fresh fibre. A well-maintained set of wheels is a quiet but real component of a bench's productive capacity.