Abstract: A ball point nib is produced by injection molding of a resilient or memory possessing thermoplastic resin, the integral nib body member including a ball housing cavity having a circular front opening delineated by an annular lip and communicating by passageways to the rear of the body member. An ink transfer ball of greater diameter than the front opening is passed through the opening into the cavity, temporarily pressure expanding the opening by pressure deforming the lip which returns to its initial state following the passage of the ball. In forming the body member a mold is employed including stationary front and movable rear mold sections having registering first and second mold cavities. An axial first core is axially movable a limited distance in the first mold cavity and has a conical rear face provided with peripherally spaced protuberances and a lip forming undercut at about the plane of the first mold cavity front face when the first core is in its forward position.