A method for manufacturing a rotor assembly of an electric engine, comprising: loading a first and second plurality of magnets in a magnet insertion tool, loading a sleeve in the magnet insertion tool: performing an insertion movement of the first plurality of magnets with respect to the second plurality of magnets using the magnet insertion tool, wherein the insertion movement comprises: moving the first plurality of magnets in a radial direction of the sleeve; moving the second plurality of magnets in an axial direction of the sleeve; and expanding a radius of the sleeve in the radial direction using the magnet insertion tool during the insertion movement.