A method of manufacturing a power tool includes forming an armature by placing an electrically insulative sleeve on an armature shaft, securing a lamination stack having slots therein on the armature shaft with the insulative sleeve disposed therebetween, securing a commutator on one end of the armature shaft with the insulative sleeve disposed therebetween, winding magnet wires in the slots in the lamination stack and securing ends of the magnet wires to the commutator, and molding thermally conductive plastic to at least partially encase the magnet wires in plastic. The armature is then disposed in a stator to form an electric motor and the electric motor is disposed in a power tool. In an aspect, electrically insulative plastic is molded in the slots of the lamination stack to form slot liners and around the ends of the lamination stack to form end spiders.In an aspect, the method includes disposing an electrically insulative seal around the insulative sleeve and abutting the commutator to seal any gap between an end of the insulative sleeve and the commutator.