Patent ID: 6910841

Claim:
In combination, a thread-forming screw comprising a head and a shank, the shank having a thread and a thread-forming zone at the end opposite to the head, the thread-forming zone having a tapered thread portion, wherein the shank at the end opposite to the head has an enlarged portion with a maximum diameter, in a plane perpendicular to the axis of the shank, which corresponds approximately to a mean diameter of the thread of the shank; and a workpiece of yieldable material, which workpiece has a bore with a diameter which approximately corresponds to the maximum diameter of said enlarged portion; said thread-forming screw being threaded into the bore and forming a corresponding internal thread into the wall of the bore, wherein the maximum diameter of the enlarged portion is sized such that withdrawal of said thread-farming screw from said bore will cause said enlarged portion to destroy the internal thread; wherein an entire length of said tapered thread portion, as measured along the axis of said shank, is less than an entire depth of said bore.