The last task to wrap up the upper skins section of the left wing was to machine countersink the inboard nutplate holes so that a dimpled skin could fit in them nicely. This was just a matter of using my countersinking cage until my sample coupon could fit into the dimples and sit flush, though it did cut away quite a bit and generate a lot of metal chips. I'll need to get some help from a friend to move this wing onto the storage cart.
Then I started looking at the flaps section to see where I left off while I was blocked on the VA-140 AEX (trailing edge aluminum extrusion). This meant measuring a couple of pieces of VA-140 and trimming them to the initial dimensions specified, to prepare them for finer measurements and trimming.