More Main Spar Nutplate Drilling

I finished up drilling the fuel tank attach plate nuts and this morning I began riveting the plate nuts to the spar flange.  This was pretty straight forward, so I won't bore you with more details.

Once all the fuel tank plate nuts were riveted to the spar, I started drilling the inspection cover plate nuts on the bottom side of the wings.  The ritual was pretty much the same as for the fuel tank attach plate nuts.

  • Make a test sample out of 0.032" aluminum for a #6 hole. (drill, debur, and dimple).
  • Drill a series of holes in the scrap aluminum angle with a #40 drill bit.
  • Eyeball center of hole and cleco into place.

When I got the countersink cutter where I thought it should be, I noticed that the countersink cutter was cutting all the way to the edge of the spar flange.  These nutplate holes are pretty close to the edge of the spar flange, but I didn't expect the countersink to cut that closely.  Therefore, I went on a pilgrimage to other builders web site's.  I found a number of other builders who's holes looked the same.  Anything shallower and the test sample didn't sit flush to the spar flange.

This was again time consuming, but after figuring out the fuel tank nutplates, this went pretty smoothly.  However, I am not sure how Van's counts out their parts, but I was one nutplate short (K1000-06).  I will need to call Van's to get an additional nutplate...