Some of the rivets I used to install the nutplates on the F-704 carrythrough bulkhead covers were a little proud of the surface. I used my flat needle file to file them down. Note the tape on the file above and below the area used for filing...to prevent gouging the cover itself.

I also reinstalled the 1/4" nutplate for the bellcrank attachment.

Then, I decided to lay out and drill attachment points which will ultimately be used to attach the side panel bottom flanges to the floor pans.

Once the screw holes were drilled to #19, I used the nutplate jig to drill holes for nutplates.

Ready for countersinking.

I used a piece of scrap 1/8" thick material to prevent the countersink from losing it's pilot. However, I didn't realize that a couple of these pans were only .025 thick. I really should have dimpled these holes instead of countersinking.

...but since I countersunk the sheet, the head of the rivet is a larger dimension than the material thickness, so I need to countersink these nutplates a little bit, too.

All nutplates installed on all four floor pans.