A combine harvester thresher includes a combine harvester threshing drum formed with a helical auger flight and which is mounted for rotation in a threshing direction for threshing crop cuttings to form threshings. The helical auger flight has a leading end directed into the threshing direction and an opposed trailing end directed away from the threshing direction, an outer face and an opposed inner face angled toward the threshing direction for driving cuttings to the threshing drum for threshing in response to rotation of the threshing drum in the threshing direction. A sacrificial shield and wear plate is releasably attached to the leading end of the helical auger flight for shielding the leading end of the helical auger flight from impacting cuttings and for deflecting cuttings to the inner face of the helical auger flight in response to rotation of the threshing drum in the threshing direction.
