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40 Polishing is a process that consists of holding the parts, large and small, on wheels of various diameters and widths that have on their edges or peripheries leather coated with emery dust which adheres to glue with which the wheels are coated. The final polishing (plate polishing) is done with wheels made of discs of calico, which assume a certain rigidity suitable to the work when they are revolving at high speed. The disc or wheel of calico discs is called a "mop" and the process is termed "mopping," to distinguish it from the coarser polishing. The calico is impregnated with grease and tripoli or rouge powder and also powdered lime or whiting.

The polishing shops resound with the whir of the polishing lathes and the air is largely impregnated with dust of steel, emery, glue, and leather. The operators are supposed to wear respirators, goggles, etc., to protect their lungs and eyes, but more often discard them when the foreman's eye is removed—one instance of where a paternal Government legislates for the workers' welfare without very much gratitude on the part of the operators.

Practically all parts come to the polishing shop because, without a highly polished surface on painted and plated work, imperfections would be very much magnified when the machine was turned out.

When the parts leave the polishers they are not chemically clean, and if they were immersed in the plating bath or enamelling vats before being cleansed to remove all trace of grease, the plating and enamel would peel off. They are therefore thoroughly scrubbed with chemicals to remove the grease, and when dry are placed in plating or enamelling vats.

The former is, of course, an electrical process, and consists broadly of depositing metal (nickel) from a