Positional control features between replaceable units of an electrophotographic image forming device

A replaceable unit for an image forming device having features for aligning the replaceable unit when installed in the image forming device and to ensure alignment between the replaceable unit and a detachable unit attachable to the replaceable unit. End walls support a photoconductive drum and have a first bullet nose, second bullet nose and stop arm used for alignment of the replaceable unit in a frame of the image forming device. Support members are on a top surface of the bottom plate with a top planar surface of one of the support members forming a rotational stop and a datum surface for the detachable unit when attached. A mounting channel in one end wall provides a second datum surface for the detachable unit and a mounting channel in the other provides a deskewing plug to adjust axial alignment between the photoconductive drum and a roll in the detachable unit.