Abstract: Spinnerette assemblies for forming synthetic fibers whereby a relatively thin orifice plate is compressively sealed against a planar face of a mounting block. The spinnerette assemblies preferably include a mounting block having a planar mounting face and a least one supply bore having a discharge opening at the mounting face. A planar orifice plate is positioned in contact with the mounting face of the mounting block and includes a capillary opening in fluid communication with the discharge opening of the supply bore. A series of attachments (preferably screws) circumferentially surround the capillary opening of the orifice plate so as to compressively rigidly fix the orifice plate to the mounting face of the mounting block and thereby seal the capillary opening against fluid leakage. Most preferably, the attachments (e.g.

Abstract: Fibers which contain potentially superconducting material are dry spun by the steps of preparing a suspension of potentially superconducting powder in a thickened solvent; preparing a solution of fiber-forming polymer; supplying the suspension and the solution to a spinning apparatus; in the spinning apparatus, arranging the solution and the suspension in a bicomponent arrangement; extruding the arranged solution and suspension from a spinneret as a bicomponent filament; and removing the solvent from the filament.