A catheter (12) has a metal deflection beam (30) with rectangular cross-section and one or two fiber puller members (28A, 28B) for predictable on-plane bi-directional deflection. Each fiber puller member is anchored at its distal end to a respective surface of the beam by a metal ferrule (31A, 31B) that is crimped onto the distal end. The ferrule is shaped to provide a flat outer underside that can lie flat against a beam surface and a thin planar distal section that is welded to the beam. With a distal end of the beam sandwiched between the thin planar distal section of two ferrules, the ferrules and the beam can be welded together by a single laser pulse.