A self drilling fastener for use in a friable material mounted on a member comprises an elongated body having an axis, an enlarged head having torque transmitting surfaces therein, a proximal portion, an intermediate portion, a distal portion, and a drilling tip generally opposite the enlarged head. The proximal portion has a threaded exterior having a root, a crest diameter, and a thread height. The intermediate portion has a threaded exterior having a root, a crest diameter substantially smaller than the crest diameter of the proximal portion, and a thread height substantially smaller than the thread height of the proximal portion. The distal portion has a threaded exterior with a root that tapers toward the drilling tip, a crest diameter substantially smaller than the crest diameter of the proximal portion, and a thread height substantially smaller than the thread height of the proximal portion.