C. H. Henderson: Cutting Mica.

Manufacturer and builder 7/1893

At the glass-house the mica is put into shape for shipment. The blocks vary greatly in size. One from the Wiseman mine, near Spruce Pine, is reported to have been 6 feet long by 3 wide. Pieces a yard in diameter have been obtained at the Ray mine, in Yancey county, and similarly large plates have been found in Siberia, but these are exceptional. The average block is little larger than the page of a magazine, and is generally less than six inches in thickness. It separates very readily into sheets parallel to the base of the prism. It is estimated that this cleavage may be carried so far that it would take three hundred thousand of the mica plates to make an inch. It is needles to say, however, that such a thickness is not suitable for service in stoves and furnaces. The mica is generally split into plates varying from about 1/8 to 1/64 of an inch in thickness. In preparing these plates for market, the first step is to cut them into suitable sizes. Women are frequently employed in this work, and do it as well as, if not better than men. The cutter sits on a special bench which is provided with a huge pair of shears, one leg of which is firmly fixed to the bench itself, while the movable leg is within convenient grasp. It is requisite that the shears shall be sharp and true, for otherwise they will tear the mica.

The patterns according to which the mica is cut are arranged in a case near at hand. They are made of tin, wood, or pasteboard, according to the preference of the establishment. Generally they are simple retangles, varying in size from about four square inches to eighty.

- C. H. Henderson, in the Popular Science Monthly.

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