Abstract: Two vertically aligned elevators, each being adapted to support a stack of blanks, elevate the blanks to a magnetic blank separator and conveyor. A releasable stack support on the upper of the elevators is operative to release the stack held thereby when the stack on the lower elevator is elevated subjacent the stack of the upper elevator, with the lower elevator then supporting the merged stack of both elevators. The stack support on the upper elevator engages beneath the merged stack at a predetermined height of the lower of said elevators to permit the latter to return for another stack. A stack height sensing device automatically alternately controls the vertical movement of the elevators when supporting the merged stack for continuous upward movement of the same for separation and lift-off. A double thickness detector is provided in combination with an ejector to ensure the conveying of only one blank at a time from the top of the stack.