Abstract: A barrel apparatus for use in treating workpieces with grinding media, comprising a novel rotary barrel provided on its inner peripheral wall with a spiral flight extending lengthwise of the barrel and one or more ancillary flights extending straight or in an extremely modulated spiral form lengthwise of said barrel and intersecting the spirals of said first spiral flight, thereby accelerating the flow of the contents in the barrel to improve grinding efficiency, and further, permitting smooth delivery of the contents even when a small amount of the contents is present in the barrel.

Abstract: An improved barrel polishing process is disclosed in which pieces or parts mounted in a rotary barrel on spindles carried by the head thereof are passed through the abrasive layer formed in the barrel. The pieces are forced to turn around a vertical shaft while turning on their own axis so that they pass alternately through a denser portion of the abrasive layer and through a coarser portion. This ensures a uniform finishing of the pieces.