A device for attaching one or more balancing weights to a rotor, the rotor including first and second sets of projections, the first set of projections being positioned in a first balancing plane and the second set of projections being positioned in a second balancing plane, with the first and second balancing plane being spaced from each other along an axis of the rotor, wherein each projection is provided for supporting, where necessary, a balancing weight, wherein the device includes: a first engaging member for engaging with either a portion of the rotor at or near the first set of projections, or for engaging with one of the projections of the first set of projections, which projection supports or holds at least one balancing weight; a second engaging member for engaging with one of the projections of the second set of projections, which projection supports or holds at least one balancing weight; a first movement mechanism for effecting relative movement between the first and second engaging members; and a controller for controlling the first movement mechanism so as to cause the first or second engaging member to engage the projection supporting or holding the at least one balancing weight and impart a force to said projection, which force is sufficient enough to deform said projection so as to attach the balancing weight to the rotor and prevent or at least inhibit the balancing weight from being able to be removed from the projection.