A receptacle with an adjusting slot is adapted to receive a mounting lip of the feed assembly. A means for positioning which may include a threaded shaft threaded into a first side of the receptacle that projects into a first side of the mounting lip, is operative to move the mounting lip within the adjusting slot. A bias spring may be positioned between the mounting lip and a second side of the mounting lip, the bias spring biasing the mounting lip against the threaded shaft. Alternatively, the threaded shaft may extend threaded through the mounting lip, longitudinally retained with respect to the receptacle operative to move the mounting lip along the adjusting slot as the threaded shaft is rotated.