Assembly method for a turbomachine

The method involves pivoting a rotor (4) at a bearing housing (2), and fastening a flow-throughable housing (6) at the bearing housing facing the rotor. The housing (6) is provided with a coating (7) in an area of its inner surface. A layer is polished by the rotor when pooling the bearing housing and the flow-throughable housing from the coating by an assembly device, where the rotor is rotated when the layer is polished. An independent claim is also included for a turbo machine with a rotor pivoted at a bearing housing.