A cylindrical internally threaded fastener, open at both ends with a flange at one end that can be installed into a prepared hole from the blind side of the ultimate fastening. The insert is threaded onto mandrel of installation tool and positioned into hole. As mandrel is pulled back, the insert is expanded into the base material it is now gripping. Installation is complete when the mandrel of the tool is removed from the set insert. Also available in other sizes including metric.