Found an old prewar Lionel 1661E locomotive that was in rough shape, trying to get it running again. Among the many problems is the armature windings are "grounding out" to the armature iron, which gives the electricity a short circuit (through the motor shaft to the sheet metal body). I got brave and unwound the armature, then rewound it with new epoxy coated magnet wire. I left the original cardboard insulators at the top and bottom of the iron stack, but there is no insulation between the wire and the iron along the axial length (except of course for the epoxy coating of the wire itself). The new windings also short circuit to the armature iron & motor shaft. My guess is the sharp bending of the wire cracked the insulation and it is touching the iron.
Should I place some additional insulator between the iron and the wire? maybe wrap a layer of electrical tape under each winding? Or wrap the wires a little more loosely to save stress on the insulation? Or replace the original cardboard insulators top & bottom? I'm at a loss here, any help is greatly appreciated.