GB1441899A - Grinding and polishing tools - Google Patents

Abstract

1441899 Abrasive tools J J G G BROIDO 11 April 1975 [23 April 1974] 15025/75 Addition to 1403167 Heading B3D A grinding or polishing tool for use with a paste of abrasive substance comprises a working surface having harder positions made of for example, cast iron or steel and softer portions made of for example, copper, lead, tin or graphite, the harder and softer portions being conglomerate bodies of metal powders bonded with synthetic resins, the bodies being assembled together by a moulding or adhesive bonding operation to form a composite grinding and polishing tool. The harder portions of the tool may consist of a plate 1, Fig. 1, of a conglomerated iron foundry powder having another hard substance such as a carbide or oxide. The softer portions consist of cylindrical studs 2, 3, 4 arranged in runs and made of conglomerated copper powder and the same synthetic resin as that used for the harder portions. The studs are made by introducing a mixture of copper powder and resin into a mould, the mixture being hardened cold or with heat and pressure. The studs are trued at one end and inserted into a circular mould in concentric circles. A mixture of iron powder and resin is then introduced into the mould to fill the spaces between the studs. The composite plate is then ground true on both faces and adhered to a rigid supporting plate 5. In another embodiment, the harder and softer portions consist of alternating sectors 6, 7, 8, 9, Fig. 3, which are moulded and adhered to a rigid supporting plate 5. In a similar embodiment having identical sectors, each sector consists of a matrix of iron foundry powder and resin having embedded copper studs. In another similar embodiment, the sectors are subdivided into annular segments of metal powders of different hardnesses, such as iron foundry powder and copper powder, alternating both radially and circumferentially. In a further embodiment which functions as and edge wheel, the tool is in the form of a composite circular plate 17, Fig. 5, which is made of iron powder bonded with synthetic resin and having peripheral teeth 18<SP>1</SP>, 18<SP>11</SP> between which are moulded inserts 19<SP>1</SP>, 19<SP>11</SP> of copper powder bonded with a resin. Such a tool may be formed as a long cylinder which is then cut into discs, each being mounted on a shaft 20. A manual tool for the apertures of wire drawing dies consists of a core 21, Fig. 7, in the form of a rod of conglomerated copper and an outer sheat 22 of conglomerated iron or steel powder.