Abstract: A rewind spindle has a bearing defining a rotation axis and a main rod supported on the bearing for rotation about the axis and having an outer face forming a part-cylindrical outer surface centered on the axis and extending angularly at most about 180.degree. of the axis and an inner face lying wholly within an imaginary cylinder centered on the axis and coextensive with the outer surface. This inner face has a lower end forming an axially directed seat and an upper end. A filler rod has a lower end complementarily interfittable with the seat, an axially opposite upper end, a part-cylindrical outer surface of the same radius of curvature as the imaginary cylinder and outer surface of the main rod, and an inner face.