GRK's R4â„¢ self-countersinking screw has a patented underhead with saw-blade like cutting teeth and six self-contained cutting pockets. Together they act similar to a circular saw-blade, transporting the drill dust away from the edge of the screw hole while cutting a perfectly clean hole into even ..
#6 and #8 screws use T-15 bit; #9, #10, and #12 use bit T-25. Self-tapping, countersinking head; W-Cut thread design. Climatek coated for all weather corrosion protection conforms with ICC#2442. For use in wood, particle-board, cement fiberboard, plastic, and sheet metal...