An electromagnetic drive mechanism (10) comprises a rotor (50) configured to rotate within a stator (30). The rotor (50) and stator (30) have multiple poles (56, 36), wherein each pole comprises a radial inner portion (564, 362) and a radial outer portion (562, 364). The radial inner portions (564, 362) and radial outer portions (562, 364) of the rotor (50) and stator (30) have different heights, forming a step (566, 366) between the radial inner and outer portions of the rotor (50) and stator (30). This configuration allows for overlapping radial surfaces in addition to overlapping axial surfaces during operation of the drive mechanism (10), thereby increasing the total overlap area and thus the reluctance torque, and potentially improving response speed while allowing for a more compact device (10).