Conforms to I S : 1237 and I S : 1706 The instrument is intended to determine the resistance to wear by abrasion of natural building stones and cement concrete flooring tiles. It comprises of a grinding disc rotating in a horizontal plane, encased in a circular tray. The grinding path is driven by a motor at 30  1 RPM with the help of reduction gears. The specimen is held loaded with a net load of 30 kgs. On grinding path with the help of a loaded beam.  An automatic revolution counter with a microswitch is provided to cut off power to the motor after every 22 revolutions. Wired for 230V., sph. 50 Hz.