Abstract: The present invention discloses an improved rotor disc for a refiner and its method of formation. The invention comprises a plurality of blade members spaced apart by a spacer between each adjacent blade member. Dams may be provided on the spacers. In forming the preferred disc, the plurality of blades and spacers are secured one to the other to form a blade segment. A plurality of blade segments are affixed one to the other to, in turn, form the disc. The invention is characterized by an absence of any mounting plate or base member. The method of the invention is characterized by a continuous weld along either of the inner circumference or the outer circumference of the disc.