Apparatus for making dual-component thermoplastic fibers, such as glass fibers, comprises a spinner having an orificed peripheral wall for centrifuging fibers from thermoplastic material, the spinner having vertically aligned compartments with first and second thermoplastic materials in alternate compartments, and a series of elongated orifices in the peripheral wall in communication with each of two adjacent compartments to enable centrifuging of both the first and second thermoplastic materials from a single orifice.