GB1296297A - - Google Patents

Abstract

1296297 Abrasive tools BARNES DRILL CO 29 June 1971 [17 Sept 1970] 30326/71 Heading B3D A filamentary cutting tool comprises a plurality of elongated cutting filaments 11 and a matrix 12, the filaments being imbedded in the matrix and all extending in substantially the same direction with the ends of the filaments being exposed at the surface of the matrix to cut a workpiece, the matrix being substantially made of a large number of solid microparticles 14 and a thermosetting plastic 15. The microparticles may. be of glass, mica or metal, of spherical shape less than 44 microns in diameter and may comprise 75% of the matrix, the remaining 25% being the thermosetting plastic which may be epoxy resin. The filaments may be high hardness steel 0À007 inches in diameter and spaced apart by a distance of about 0À020 inch. The tool may be made by coating the filaments with a mixture of the particles and plastic, placing the filaments on a sheet of cloth, heating the plastic to form a composite sheet of cloth and filaments, and bonding a number of such sheets together to form a block from which a number of tools can be cut. In apparatus for forming the sheets, a cloth sheet 16, Fig. 7, which may be coated with the matrix material, is placed on a drum 21 rotatable by a motor 26 as a wire 11a guided over pulleys 27, 28 and passing through a reservoir 32 of the matrix material is wound on the drum, the pulleys and reservoir being carried by a nut 29 engaging a lead screw 34 driven by the motor 26. The plastic of the matrix is heated to hold the wire on the cloth which is then cut along its length to form the sheet 17, Fig. 5. After trimming the edges 20, a number of sheets are stacked and bonded together to form the tool. The tool may be in the form of a grinding wheel or a honing stone for honing cylindrical bores.