Aluminum Oxide Versus Garnet as a Wood Abrasive

A comparison is made of aluminum oxide and garnet as surface-coated abrasives in woodworking. Garnet as found in the native state breaks into wedge-shaped pieces that when cemented to a surface of paper or cloth continue to fracture so as to produce further sharp edges. Aluminum oxide is a manufactured product, made in the electrochemical furnace by fusing bauxite and adding coke and iron. The hardness, toughness, and fracture of the two abrasive materials are compared. A table is given that covers time-study tests of belts used in a woodworking plant, with the labor and material costs.