A mold for molding a drum shaped magnetic core having two flanges connected by a coil winding core portion. The mold includes a die defining a cylindrical cavity having an inner diameter substantially equal to an outer diameter of the flanges. A pair of die inserts are movable in an orthogonal direction relative to the cylindrical cavity and define a diameter of the coil winding core portion of the drum shaped magnetic core. The diameter of the coil winding core portion is smaller than the outer diameter of the flanges. An upper punch and a lower punch are inserted into the cylindrical cavity from a corresponding end opening of the mold such that each forms a flange. A central punch is disposed coaxially within one of the punches to form the coil winding core portion.