After the fun with the bottom skins I decided to do the final fitting of the boarding steps. I held off drilling the bearing blocks until the skin was riveted to the baggage ribs to keep the rib from moving around.
I put the steps in place and started the bolt hole by match-drilling through the bearing block with the angle drill. I then took the steps back off and finished the drilling on the drill press.
I masked off the skin where the boarding step flange will be. I prepped, primered and then painted (automotive rattle-can) this area on the skin to prevent corrosion. I also painted the inside and outside of the portion of the step that will be in the fuselage or interface with the skin to prevent rust.
I left 3/4" of the tip of the step torque tube with only primer. The fit of the tube into the bearing block is tight. There is no room for any more paint.