Abstract: An improved navel member positioned in the cover of the spinning rotor of an open-end spinning frame includes a barrel having a longitudinal passageway extending therethrough. The axis of the passageway is substantially coincident with the thread path as it exits the spinning rotor. A cylindrical insert is fixed in the barrel passageway and includes a longitudinal channel therethrough through which the thread actually passes. A plurality of spaced longitudinal grooves in the inside wall surrounding the longitudinal channel receive elongated ceramic rods partially embedded therein. The rods form a plurality of spaced obstructions around the periphery of the longitudinal channel. The periphery of yarn passing through the navel member intermittently engages and disengages the ceramic rods causing an improved roughening and bulking effect.