Patent ID: 8192123

Claim:
A self drilling fastener for use in a friable material with or without an underlying support member at the point of use, comprising: an elongated body having an axis, a threaded exterior having a root, and an enlarged head having torque transmitting surfaces therein, a proximal portion, an intermediate portion, a distal portion, and a drilling tip generally opposite said enlarged head; wherein said body is solid along said proximal portion; said proximal portion having an axial length and threads for gripping said friable material having a root with a root diameter between about 3/16 inch and about 5/16 inch, a crest with a crest diameter between about ⅜ inch and about ⅝ inch, and a thread height, wherein said crest diameter is about twice said root diameter; said intermediate portion having an axial length and threads for gripping said member having a root that tapers with a root diameter between about ⅛ inch and about 5/16 inch, a crest with a crest diameter between about ¼ inch and about ½ inch, and a thread height substantially smaller than said thread height of said proximal portion; said distal portion having an axial length and threads for drilling into said member with a root with a root diameter between about 1/16 inch and about 3/16 inch that tapers toward said drilling tip, a crest with a crest diameter substantially smaller than said crest diameter of said proximal portion, and a thread height substantially smaller than said thread height of said proximal portion.