The two bottom R918 rudder attach strips were fabricated from the provided raw material... Then, the rudder horn box was trimmed to final size and clecoed on the structure, the fit was perfect so I went ahed and match-drilled it... Now that the rudder horn was completed, I could clamp in place my two bottom attach strips that were previously built and back-drill them from the top with the prepunched hole in the skin as a guide... Finally, the rudder was completely deassemble to be deburr, dimpled, cleaned and primed for final assembly!