Abstract: Described herein is a method of manufacturing a housing for the stator of an axial flux permanent magnet machine. The housing has a cylindrical wall including a metal outer ring lined with a polymer inner ring. The method includes positioning the metal outer ring in an injection moulding machine, and with the injection moulding machine injection moulding a polymer resin onto an inner surface of the metal outer ring to fabricate the polymer inner ring. The polymer inner ring includes a gripping surface arranged to grip a portion of the outer ring, for example moulded around a formation on an inner surface of the metal outer ring. The housing is manufactured using the metal outer ring and the polymer inner ring.