Apparatus for injection molding

An apparatus for conducting melt in stack mold arrangements comprises at least one tubular body having a passage there through for conveying melt, an interface member mounted to at least one tubular body at a terminus of the passage for conducting melt between the tubular body and a mating mold member engaged by the interface member, and a length adjusting device interposed between the interface member and the tubular body and having a wedge member and means for setting the transverse position of the wedge member relative to the longitudinal axis of the tubular body whereby the overall length of the combined tubular body and interface member is established. A sprue bar assembly comprises a sprue bar segment, a nozzle and a length adjusting device interposed between the nozzle and the sprue bar segment having an adjustable wedge member for establishing the overall length of the sprue bar assembly.