Rather than rivet on the nut plates and then machine countersink, I decided to use the technique I had used to install the wing spar nut plates
So I used the same tool I had made to provide a robust guide for the #19 countersink.
Once I had aligned and clamped the guide, I used the microstop to machine the countersinks. I used a scrap piece to set up the depth.
I machined about 0.011″ deeper than for a flush #8 screw. This seemed to give a countersink width of 0.354″, which just happened to be the same as for the wing spars.
I used the squeezer to set the nutplate rivets. Vans suggest AD3-4’s for these, but I found AD3-4.5’s better.
So that’s Section 16 finished for the R Wing. It will be a few days before Tim will be available for starting the L Wing riveting, so I’m going to get on with preparing the Leading Edge ribs … more deburring, oh good! : (