Patent ID: 8257402

Claim:
A closure for setting engagement with a structural member and comprising: (a) a substantially cylindrical body having an outer cylindrical surface relative to a central closure axis; (b) a guide and advancement flange extending helically about said outer cylindrical surface and having a forward advancement direction relative to said closure axis, said flange having a leading surface and a trailing surface relative to said forward advancement direction; (c) said trailing surface being compound in contour and including an inward substantially horizontal surface and an outer raised portion; the leading surface sloping outwardly rearwardly; (d) a driving structure for rotating and torquing said body to a preselected torque; and (e) said body having an axially aligned bore opening on a trailing surface of said body; said bore having a left handed thread that includes a plurality of complete revolutions of the thread about the bore therein that is sized and shaped to be adapted to receive a removal tool with a mating left handed thread for removing said body subsequent to installation.