The next step was to cleco each z-bracket to the spar through the center holes that were previously drilled. I then used a square to make sure the brackets were square to the spar. Once each bracket was square and securely clamped to the spar, the remaining two 3/16" holes were drilled in each bracket. I had a little trouble with the inboard most bracket. On my left wing, I followed the plans and drilled the z-bracket and then riveted the nutplates to the spar. The riveting was awkward with the wing in the jig. So,,,for my right wing, I installed these nutplates while the spar was sitting on the workbench and before the main ribs were riveted on. This worked fine until I went to drill the z-bracket holes. I had to use a smaller drill and carefully drill through the nutplate screw holes without buggering up the threads. Then I had to remove the bracket and drill the holes to the full 3/16" size called for in the plans. It worked out ok and I didn't hurt the threads but this actually slowed things down a bit rahter than speeding things up. Oh well, live and learn.
Make sure brackets are square to spar; clamp securely
