Abstract: A winding core for magnetic tape is adapted for stacking between like winding cores. The core has a substantially annular body with top and bottom substantially annular body surfaces, an outer circumferential body surface to wind the tape about, a discontinuous inner circumferential body surface and a set of recess surfaces extending between the annular body surfaces and between portions of the discontinuous inner circumferential body surface. The recess surfaces define a circular array of recesses for the core. Opposed sets of projections rise from the top and bottom annular surfaces. Each set forms a circular array; and each projection is adapted to mate with a recess of a like top or bottom sandwiching winding core. The projections of each array of projections are spaced to mate with every third recess along the array of recesses of a sandwiching core.

Abstract: A stack mold stabilizer for causing the multiple mold plates of a stack mold to maintain their required even spacing at all times during operation. The stabilizer includes a rack and pinion mechanism for maintaining an equal distance between the mold plates of the stack mold. The stack mold includes at least three mold plates with the mold plate at one end being fixed and having a first rack gear fixedly mounted to its side. The center mold plate has a pinion gear rotatably mounted thereon. The teeth of the pinion gear are maintained in firm meshing engagement with the teeth of the first rack gear by a first idler roller mounted on the center mold plate. The third mold plate has a second rack gear fixedly mounted to its side and has teeth which are kept in firm meshing engagement with the pinion gear by a second idler roller mounted on the center mold plate.