a method of assembling and manufacturing a laminated rotor is provided which uses laminations having a thin bridge thickness . different techniques are provided for preventing the molten material used in the casting or injection molding operation from leaking or seeping between the laminations during casting . in one technique , the laminations are stacked and oriented in the conventional way , and then both axial and radial pressures are applied to the stacked laminations to hold the laminations in position for the casting process . in another technique , the laminations are formed or extruded with a lip or collar portion that fit in a countersunk portion of an adjacent lamination and forms a wall or barrier between the laminations to prevent the leakage of the molten material during the casting or injection molding operation .