Tonight consisted of three tasks -- and I will be at these for quite some time.
First, I primed a bunch of nutplates. They are plain steel, so if anything ever needed priming in the Pacific Northwest, these nutplates would be at the top of the list. Note that the photo shows two types. I only used the flat (small) ones, but figured that I may as well prime some of each.
Then each center hole was drilled to 3/16" (instructions are very vague here), and the bottom of each hole was deburred.
Next up was to create a template piece of metal to use for testing countersink depths. The aluminum test piece is the same thickness as the tank skins (0.032"), and dimpled for a #8 screw.
I started installing nutplates, one or two at a time, and riveted them in place. The nutplate will sever to center the countersink bit.
Set up my new single-fluke bit and gingerly drilled to the correct depth, testing with just the screw and also with the metal template to make certain that all is correct. Think that I need to go just a touch deeper; however want someone else to look at my work first. Easy to drill deeper, but not so easy if the holes are too deep...
Total Time: 2 hours