Abstract: An axial machine having a wedge that drives a plurality of pistons and a retainer plate for maintaining the slipper shoes in contact with the wedge. A center positioning mechanism for the retainer plate in which the slipper shoes placed on the wedge have a portion extending through a respective hole in the retainer plate, with each of the slipper shoes engaging a point on the side of its respective hole to restrain the retainer plate from movement parallel to the planar angular surface of the wedge. Also described is an oil separation system for removing oil from the gas to be compressed such that the removed oil drains into the oil sump. An oil lubrication system has a cavity around the drive shaft to receive oil from the sump, and disburse the oil through a passageway to discharge ports in the wedge to disburse oil on the planar angular surface of the wedge.