Cushions, methods, and manufacturing systems for making the same are disclosed. The cushions may be foamless such as being made from a body of entangled and/or intertwined polymeric strands. The manufacturing systems may include a die such as die bars having a plurality of orifices that cooperate with a plurality of receptacles and actuators for discharging a plurality of fasteners from the receptacles, through the die into the cushions. In a refinement, the die may be heated such that a skinned over membrane is created in the cushion to retain the plurality of fasteners. A trim cover may cooperate with the plurality of fasteners such that it is attached to the cushion.

A riveting method involves laying a second to-be-fastened member on a first to-be-fastened member having a prepared hole, then driving a metal rivet into the prepared hole. The prepared hole includes a hole portion having a substantially cone or truncated cone shape. The rivet includes a tapered, grooved first shaft portion. The first shaft portion includes a tip end portion whose diameter decreases toward a tip end side. A difference between a circumferential length of an inner wall surface of the hole portion and a circumferential length of the first shaft portion at a position where the inner wall surface and the first shaft portion are in contact with each other after driving of the rivet is divided by the circumferential length of the inner wall surface to obtain an interference, and a maximum interference that is a maximum value of the interference is 3 to 13%.