Abstract: Distortion-free method of mounting an end piece member on a thin-walled hollow tube member, particularly in the assembly of photoreceptor drums and the like, includes the steps of supporting an expandable end piece member within the chamber of an air centering device with its central axis aligned vertically; applying a layer of flowable adhesive to the interior surface of an open end of the hollow tube member; freely suspending the tube member above the end piece member with the open end remaining free of radial distortion and directed toward the end piece member; centering the tube member, by means of the air centering device, to concentrically align the tube member with the end piece member; inserting the end piece member into the tube member; deformingly expanding the end piece member until the layer of flowable adhesive is sufficiently compressed between an outer peripheral edge of the end piece member and the interior surface of the tube member, so as to absorb any dimensional discrepancies therebetween;