A method for shaping gemstones comprising the steps of placing a template in contact with a grinding wheel and locking against translational movement an element holding the template; removing the template from adjacent the grinding wheel and placing the template on the locked holding element at a position spaced from the grinding wheel; placing a guide plate in contact with the template and retaining the guide plate against movement; releasing the locked holding element and permitting movement of same toward and away from the grinding wheel and the retained guide plate; and setting a stone to be shaped in the position formerly occupied by the template.
A lapidary machine is provided with a grinding wheel and a removable hinged adjustable fixture arranged to swing toward and away from a grinding surface on the wheel and having an adjustable slide carrying a guide bar and a swing arm on which is journaled an arbor having a chuck for a dop, a template, and a turning knob. The template is swung against a guide surface on the guide bar and turned to establish the grinding pattern of the grinding wheel on a cabochon blank or the like mounted on the dop.
A grinding tool is provided that is especially designed for the accurate and efficient grinding of overhead camshaft motor valve clearance discs. The tool hereof includes a tool outer casing adapted for retainment in the clamping fixture of a grinding machine, a disc retaining head rotatably carried by the housing, and an axially aligned release rod shiftably carried within the retaining head and housing. In operation, the disc is retained by a lubricated force fit within a retaining head counterbore, and the grinding tool positions the disc in grinding contact with the generally planar grinding surface of a rotatable grinding wheel. The rotational mounting of the retaining head within the tool housing allows for rotation of the disc relative to the grinding wheel surface, thereby enhancing the even grinding of the disc.
A faceting device for holding precious stones during cutting and polishing the facets. It comprises a two-part indexed quill member having a mounting at one end for mounting and locking the stone position relative to a horizontally rotating abrasive lap wheel and a cylindrically configured tailstock element at the other end. The tailstock is tightly and diametrically received in a backplate containing trigonometrically positioned multiple rows of grooves which obtain a multiplicity of different angular settings. The upper and lower portions of the quill attach by a male rod in the lower quill which is slidably received in an elongated opening in the upper portion where a hand set screw extending radially into the upper quill portion can be turned against the male rod to secure the lower quill in angularly rotated adjusted position. The backplate attaches to a vertical mast and is locked at desired heights by a hand set screw threaded radially through a backplate collar and turned against the mast.
