Abstract: A self-anchoring fastening device for laminating sheets of material such as sheets of metal used in constructing metal buildings. The anchor comprises a collapsible anchoring portion having radially expanding anchoring strips, which will not pull out of a hole drilled in the sheets. Threads internal to the expandable anchor cooperate with threads on a bolt inserted therein to collapse the expandable anchor, providing anchoring strips over one sheet such that the expandable anchor cannot be pulled out of the hole. A washer between the base of the collapsible anchoring portion and one sheet provides for a waterproof fastener such that the building will be watertight. The anchor is easy to install by placing the anchoring device though aligned apertures in two sheets and then turning the bolt relative to the collapsible anchoring portion to extend the radially expanding strips thus securing one sheet to the other.