A stator for a progressive cavity pump or motor, comprising: a stator housing having a longitudinal axis; and a stator insert of a material moulded within the housing, the stator housing further comprising, an outer tube having an inner surface; a plurality of framework elements disposed on the inner surface of the outer tube; at least one recess in the inner surface of the outer tube; wherein the conjunction of said framework elements and said at least one recess define a plurality of chambers receiving insert material therein whereby said insert material is mechanically fixed axially, radially and torsionally within the outer tube.