A disc-shaped test piece is mounted to the spindle and driven by an electric motor at a constant velocity. A free-running abrasive wheel is placed against the specimen by means of a mass acting via a pivoted crank. The planes of the specimen and the abrasive wheel shall be inclined at an angle of 15° or 25° to each other based on the specific test piece.
Each test is composed of a trial run, a wearing-in period and five test runs. The values of mass loss determined from the 5 test runs are measured with a balance to calculate the abrasion resistance index.