A new, facile, and versatile technique of scientific and industrial interest is introduced for the first time to spin an additive-free polymer solution into the hydrophilic nylon 6 hollow fiber membranes. Specifically, the technique employs a single orifice spinneret immersed directly into the coagulation bath. Hollow fibers are produced when the thickness of gelled surface layer is smaller than the fiber radius, which is in turn determined by the orifice diameter. Otherwise, bore-free fibers are expected. More specifically, the morphology of hollow fibers can be best tailored through choosing spinning dope from different sections in ternary phase diagram of nonsolvent/solvent/polymer. The produced hollow fibers are suitable candidates for water purification purposes, especially forward osmosis and pressure-retarded osmosis.