Automakers are increasingly using hydroformed metal tubing in vehicular structures. Compared with stamped and welded metal parts, hydroformed parts weigh less, cost less, and have a higher stiffness-to-weight ratio.
That’s all well and good—until the need arises to attach other parts to the structure with threaded fasteners. Tapping threads in the tube may not be feasible because the material might not be thick enough or strong enough. Self-clinching nuts, nut plates or weld nuts are not an option, since installation requires access to the opposite side of the metal. Cage nuts are a possibility, but they require a square hole and are difficult to install.