A rotating machine has a stator and a permanent magnet rotor that is more easily made, lower cost, and lighter by virtue of a plurality of permanent magnet assemblies mounted on a rotor body. Each magnet assembly includes two facing core plate stacks supporting a permanent magnet between them. Each core plate stack is made from a plurality of core plates of substantially identical size and shape and with on or more holes in substantially the same location to form respective bores in the stack. A tie rod is formed in each bore and retains the plates in a stack via bevels in the holes of the end plates. Preferably, the tie rods also apply compressive force as a result of placing the stacked plates in an injection mold, injecting plastic into the mold to fill each bore with plastic, and allowing the plastic to cure. As the plastic cures, it shrinks so that the tie rods pull the end plates together. To enhance the pressure, the stacked plates can be compressed before and during the injection process.