Drilled the crossbar for nutplates in the center. Deburred, countersunk and riveted on nutplates with squeezer. Mounted the bar to the flap housing. Clamped the bar securely in place and drilled the bar to #40, inserted clecos as I went. Upsized holes to #30 and cleco'd again. Upsized holes to #12, used bolts and nuts to secure. Removed the bar and deburred all holes in the bar and fuselage. Drilled the end of the bar for single lug nutplates and deburred. Countersunk the rivet holes and riveted the nutplates with the squeezer. Bolted in the bar.