DRESSING STONE BY ELECTRICITY.

South Canterbury Times, Issue 2104, 19 December 1879, Page 2

DRESSING STONE BY ELECTRICITY.

Among the novel applications of electricity to the industrial arts is a new stone - dressing apparatus, which is worked by a dynamo-electric machine, and which the inventor claims will dress mill stones or other stones, and drill rock economically, with rapidity precision, and despatch. The chisel employed is fastened to a spring arm which protudes from a case containing magnets and armatubes. This spring arm, when the magnets are connected with the dynamo-electric machine, moves up and down with extreme rapidity, causing the chisel to strike a blow .at each descent. The inventor states that it can be made to strike from one to two thousand blows per minute. Wires being used in place of steam pipes enable the apparatus to be moved readily to any angle, or worked at any reasonable distance without much loss of power ; while not the least meritorious portion of the whole invention is the horizontal frame or base to which the electric apparatus is fixed. This frame is portable, and by the use of screws can be so adjusted as o cause the chisel to strike any portion of a circle with either a swift or a slow motion, the number and intensity of the blows being regulated according to the softness or hardness of the stone. By the use of this machine it is said that a millstone can be covered in a very short space of time with the necessary grooves and furrows, having the straightness regularity, parallelism so much desired in good millstone dressing. The apparatus can be worked either automatically or by hand, so as to suit the varying natures of the stone operated upon.