Minnesota Mining and Manufacturing Company

Gerald R Abrahamson

Ernest J Duwell

The present invention provides an abrasive article, particularly a cut-off wheel, having a mixture of rare earth oxide modified abrasive grains and alpha alumina seeded or iron oxide nucleated abrasive grains. Preferably, the rare earth oxide is present at a level between about 0.1 wt-% to 10 wt-% of the abrasive grain, based on a theoretical oxide basis. In one embodiment, the rare earth oxide modified abrasive grains are rods.

Abrasive articles comprising a blend of abrasive particles

A rotary brush with removable brush elements is provided. The brush elements are disposed on a hub in a radial display. The brush elements include a resiliently flexible element which permits the brush to deflect at a greater angle from a rest position than the angle of deflection of the bristles of the brush from a normal position when the hub is rotated with the bristles in contact with the workpiece.

Method of making rotary brush with removable brush elements

A cutting element adapted to be used in a rotary drill bit is made by positioning in an appropriately shaped die cavity a quantity of a mixture of tungsten carbide and 4 to 11 percent cobalt in the shape of a crown for defining an outer surface for the tip portion of the cutting element using a pressure of less than about 600 pounds per square inch; positioning in the cavity a quantity of a mixture of tungsten carbide and 12 to 17 percent cobalt sufficient to form almost all of a base portion and at least an inner part of the tip portion for the cutting element; pressing the two quantities of the mixtures together and into the die at pressures in the range of about 10 to 15 tons per square inch; and sintering the pressed insert to form the cutting element.

Growing community of inventors

Saint Paul, MN, United States of America

Gerald R Abrahamson