An undercut anchor 2; 30, which facilitates the formation of a corresponding undercut in a blind hole for receiving the undercut anchor 2; 30, is formed to independently cut or form this undercut by rotating and spreading the undercut anchor 2; 30. Furthermore, a setting tool for forming this undercut at the bottom of the blind hole in the joining partner is proposed. Finally, a method of forming an undercut at the bottom of a blind hole using the setting tool is disclosed.

An expansion anchor is provided, which is generally comprised of a drill rod, cone tip and anchor to create an undercut. In one embodiment, the drill rod is connected to the setting tool while in another embodiment, the cone tip is connected to the setting tool. In both instances, rotation of one or the other engenders a corresponding rotation from the anchor, which forces the cone tip upwards and into the anchor, which thus forces the anchor outwards and sets the expansion anchor. A sectional coloured threading is also provided to allow an operator to determine when the anchor is sufficiently set.

A fastener for mounting through an aperture of a wall, the aperture having an aperture diameter. The fastener has an inner stud sized to fit through the aperture of the wall, the inner stud having an externally threaded shank, and further having an internally threaded bore. A spiral structure operably connects with the inner stud. An installation tool comprises an elongate body that extends from a proximal end to an externally threaded distal end, wherein the distal end may threadedly engage the internally threaded bore of the inner stud. An outer nut has an inner conduit with an internal thread that may be threadedly engaged with the externally threaded shank of the inner stud. The installation tool further includes a spanner knob threadedly mounted on the elongate body, the spanner knob having a first engagement structure that removably engages a second engagement structure of the outer nut such that the spanner knob may be used to turn the outer nut with respect to the inner stud, and thereby threadedly tighten the outer nut on the inner stud, which functions to compress the spiral structure in a washer-like structure.