Functional coating of drill screws

Claim 1

IN COMBINATION A COATED SELF-DRILLING SCREW FASTENING A FIRST IMPERFORATE PANEL IN JUXTAPOSED RELATION TO A SECOND IMPERFORATE PANEL, SAID FIRST PANEL HAVING A PREDETERMINED HARDNESS AND SAID SECOND PANEL HAVING A GREATER RELATIVE HARDNESS THAN SAID FIRST PANEL, SAID SCREW INCLUDING A HEAD HAVING DRIVING MEANS, A THREADED SHANK AND A DRILLING TIP ON THE EXTREMITY OF THE ENTERING END OF SAID SHANK OPPOSITE SAID HEAD, A COATING ON SAID SHANK AND A SUBSTANTIAL PORTION OF SAID ENTERING END, SAID COATING FILLING A SUBSTANTIAL PORTION OF THE VOID EXISTING BETWEEN THE ROOT AND CREST DIAMETERS ALONG A SUBSTANTIAL AXIAL EXTENT OF THE THREADED PORTION OF SAID SHANK WHEREBY ONLY A MINIMAL PORTION OF THE CRESTS OF SAID THREADS ARE AVAILABLE FOR CONTACT WITH A WORK PANEL, SAID COATING HAVING A LESSER DEGREE OF HARDNESS THAN SAID SCREW, SAID COATING BEING HARDER THAN THE PREDETERMINED HARDNESS OF SAID FIRST PANEL THROUGH WHICH THE SCREW IS APPLIED AND SAID COATING BEING SOFTER THAN THE SECOND PANEL TO WHICH THE SCREW IS APPLIED, SAID SCREW BEING HARDER THAN BOTH PANELS, WHEREBY SAID DRILLING TIP AND SAID ENTERING END WILL FROM A HOLE AND PARTIAL THREAD TO PULL SAID SCREW THROUGH SAID FIRST PANEL WITH SAID COATING AND ITS ASSOCIATED MINIMAL EXPOSED CRESTS ON SAID THREADED SHANK PROVIDING READILY STRIPPABLE ENGAGEMENT IN SAID FIRST PANEL TO PERMIT FREE ROTATION OF SAID SCREW DURING THE DRILLING OF SAID SECOND PANEL, SAID COATING BEING STRIPPED OFF TO SAID SCREW BY SAID SECOND HARDER PANEL TO EXPOSE THE THREADS ON SAID SHANK FOR INTIMATE ENGAGEMENT WITH SAID SECOND PANEL WHEREBY SAID PANELS ARE DRAWN INTO JUXTAPOSED RELATION.