The improvement in the millstone dress which is illustrated in the accompanying engraving is the invention of Gabriel Natcher, of Indianapolis, Ind., and two patents were granted to him April 27, 1858, for his invention, one for the dress and the other for the tool which he employs to cut the stone. The whole of the face of the stone being polished as smooth as possible, the tool which we will now describe is used. It is composed of one or more diamonds, inserted in a^handle, and when two or more are used they are to be firmly set in a row at equal distances apart. The crack or grinding surface is commenced at A. The furrows or cracks, A and.B, are produced by running the diamonds over the face* of the stone by the side of a straight ruler. The curved lines, as represented at C, are made by operating the diamond by the the side of a curved ruler. The width of the space separating the lines updn the grinding I surface of the stone is regulated by holding C the points more or less diagonally across the ^line of motion. In the usual mode of dressing stones, a pick is used, which being brought down upon the face of the stone produces the stellated fracture, thereby weakening the stone as far as the fracture extends. Thus the edges of the cracks weakened by the blow from the pick soon crumble away, wearing the face of the stone as the particles thus detached are thrown oit. All these disadvantages are entirely prevented by this mode of dress. The line cut by the diamond upon a glossy surface which has never been disintegrated by a blow from a pick is clear and distinct, having its edges shayp and fine with no disposi-tien to crumble, the cohesion being perfect up to the edge of the crack, thereby insuring a sharp corner or cutting edge perfectly straight and equal. The stone will be more perfect when dressed again upon this plan, as the diamond gets below the bruises occasioned by the old mode of dressing with a pick. The furrow is smooth, having the side upon which the grain rises a regular inclined plane. The passage of the grain to the face is uniformly checked by the lines at A, where the bran is taken off. As there is no crushing contact of the stone with the wheat, the sharp edges of cracks or small lines cutting or shaving up the grain, while no roughness or inequality is allowed although brought close together. The fl.our comes from the atone with all its nutrition, as the stones run very close; scraping the bran clean without cutting it up. There is no perceptible moisture generated in the operation of grinding by this mode, and the spouts are clean and dry, because the grain is moved to the eye by the retarding curved lines until well ground, and while the motion is less rapid, and consequently less liable to heat, the pressure being the same, when, having reached the extreme of the breast-circle, it is rapidly thrown from the stone, finding few or no irregularities to retard its progress. The inventor has sold half his interest to A. P. Ojrton, of the same city, from either of whom further particulars can be obtained.
This article was originally published with the title "Natcher's Millstone Dress" in Scientific American 13, 41, 328 (June 1858)