Abstract: The invention relates to a machining center comprising a pallet changing station in combination with a machining station. The pallet changing station includes a rotating column assembly supporting a platform on which multiple fixtures are supported and moved. A portion of the column assembly defines part of a hydraulic conduit for supplying hydraulic fluid from a fluid source to the fixture for use in clamping parts to the fixture. The integration of a portion of the hydraulic conduit with the rotating column reduces the tendency for the hydraulic conduit to become twisted during rotation of the column or for the various threaded connections of the hydraulic conduit from loosening.