Abstract: A rotor for an electric motor includes a plurality of laminated sheets assembled into a puck. The puck defines a plurality of apertures for the receipt of rotor magnets. The apertures extend in a substantially circumferential direction around the puck. Each laminated sheet includes a plurality of protrusions and a plurality of corresponding recesses configured to receive the protrusions of an adjacent laminated sheet. The protrusions and recesses are configured to engage with an interference fit. The protrusions and corresponding recesses are positioned at a greater radial distance from a centre of the puck than the apertures and each protrusion is elongate in a substantially circumferential direction of the puck.