How SMITHing works:
SMITHing is a process of scratching, scoring, marking, notching or etching the surface using flailing style cutters on a rotating cylinder cutter drum. The drum contains cutting shafts outfitted with cutters that fit loosely so they flail or strike the surface at various depths. The flailing against the shafts creates a great force whereby the surface can be removed at a rapid rate. Cutter spacing on the drum influences surface depth and finish. Adding spacers increases surface depth and coarseness. Eliminating spacers reduces depth and improves surface finish. Depending upon the type of cutters, depth of surface penetration, drum rotation and cutter pattern, a variety of finishes can be achieved from a very smooth finish (#1) to an extremely coarse texture (#10), as depicted on the following chart.