The machine consists of a hollow cylinder mounted horizontally on a study frame on ball bearings. There is an opening which can be closed with a dust tight cover to facilitate charging and discharging the drum with the material under test. A detachable shelf which extends throughout the inside length of the drum which catches the abrasive charge and does not allow it to fall on the cover. The drum is rotated by an electric motor through a heavy reduction gear at a speed of 30-33 R.P.M. A revolution counter is fitted to the frame. A tray is supplied for collection of the material at the end of the test. Complete with Abrasive Charge consisting of a set of twelve hardened steel balls, approximately 48mm dia. Suitable for operation on 440 V, 3 Phase, 50 cycles, A.C. Supply.