Section 21 Deburred Seat Ribs. Pg. 21-04 Step 7: There was no vertical strips in my seat rib holes. Step 8: Clecoed together two Rt. & Lt. Seat Rib Assys. Step 9: Final drilled #30 the eight holes in each assy. After deburring the holes, riveted together the assys. Pg. 21-05 Step 1: Final drilled #19 the nine screw holes in each of the two ribs indicated.
