Expandable abrading tool and abrasive insert and washers thereof

Abstract

An expandable abrading tool (20, 20a, 20b) disclosed includes a rotatable arbor (22) and an abrasive insert (24, 24a, 24b) having stacked washers (26) which receive the arbor and are mounted thereon in a clamped relationship. Each washer has a round outer edge including an abrasive (32) secured thereto for performing a cutting operation upon tool rotation. The washers each have a frustoconical shape that points toward one axial end of the insert. A threaded clamp (38, 40, 42, 44) which provides a means for clamping the ends (34, 36) of the insert is adjustable to increase the clamping force in order to flatten the washers and thereby control the washer diameters. The insert can thus be initially sized for use and can be adjusted to compensate for wear of the abrasive. Different embodiments of the abrasive insert include the washers with slightly smaller spacers (28) interposed therebetween in an alternating relationship, the washers directly engaged with each other, and flutes (46) in the outer edges of the washers. It is preferable but not absolutely necessary that the flutes (46) be aligned in an axial relationship along the insert length. The washers are made from a suitable spring metal, preferably a copper alloy such as bronze with a component such as beryllium, so that the clamping force required to provide the flattening thereof is not too great. The flutes (46) also lessen the required clamping force to flatten the washers.