Abstract: An assembly for precisely positioning a pair of die members beneath a reciprocating press ram, wherein a clamping assembly extends between each die member and a frame supported on a bed of the press for clamping and unclamping the die members. A self-lifting assembly provides a force which bears downwardly against the frame and upwardly against the die members for appreciably reducing frictional contact therebetween. An adjustable key is positioned for aligning the frame beneath the reciprocating ram. Finally, positioning apertures are provided for aligning the die members relative to one another on the frame.