An agitator assembly for an automatic washing machine comprises an agitator and an auger mounted to the agitator. The auger comprises a tubular body defining a peripheral surface and having a central longitudinal axis. A vane spirals around the tubular body and extends from the peripheral surface from a root having a thickness T to a tip. The vane has a width W measured from the peripheral surface along a line perpendicular to the central longitudinal axis to the tip. The vane is formed by a plurality of ledges, with adjacent ledges joined by steps. With this configuration, the vane can have a relatively small root thickness T and a relatively large width W.