[September 17, 2006]

Today I countersunk all the #40 holes for the rivets that hold in the nutplate on the main spars. I read ahead a little and decided to do all the nutplates on the main spar at once - these include the nutplates for the fuel tanks, the ones for the inspection plates, and 2 nutplates on the face of the spar that tie into the center section. It took me probably 20 minutes to confirm how these nutplates get attached properly, and what rivets to use for them. Van's does a typical job of spreading out all the info you need over multiple diagrams.

I read ahead a little and saw that Van's tells you to prime the spar where you countersunk. I think they are refering to where you countersink for the #6 and #8 screws, but I am going to play it safe and do the all of them.

One thing that I wish I did was do everything in a more uniform manor. My second spar went a lot faster than the first one because I didn't change bits and countersink settings all of the time. Here is the order I used:

1) Drill all holes to #40 in both spars
2) Countersink all holes except for the diagonal nutplates on the top and bottom of the root end of the spar.
3) Countersink the diagonal nutplates.

I found that the forward nutplate rivet holes needed a click or two less on the countersink bit. If I used the setting I used for all of the other holes, it was a hair too deep. I think this is because those holes are close to the edge and the countersink cage wanders down a tad.

This shot is to show the rear side of the spar countersunk for the two nutplates.



Last Modified: May 19, 2024