Practice kit question

[JetMech72]

I'm working on the aileron practice kit and have a few questions. I'm not sure what I am building...it is Figure 1 on the first page. You rivet a 11" piece of angle to a 2 1/4" plate, which is also riveted to a 2 1/4" plate. The pic of it is below.

Anyway, it calls out for (12) #30 holes which will be filled with (4) AN426AD4-4, (6) AN470AD4-4, and (2) MSP-42 rivets.

Since the angle piece is a bit thicker, should it be countersunk?
When I dimple the thinner top piece, do I use the 1/8" die because I am using size 4 rivets?

That's what I did and there are some gaps between the pieces. I don't know if this is a technique problem or what. For now I am using a hand squeezer and I'm wondering if that is the problem.

[JetMech72]

My plant in Cheshire was given notice that it is to be closed this year and moving to Singapore and Georgia. Pratt isn't what it used to be. I don't care for the winters here either...

When I countersunk the bottom, thicker piece, I did it just enough for the rivet head to sit flush. I take it I should have done it more, so that the dimpled sheet above would sit flush instead? Also, what is this assembly to be used for?

[JetMech72]

Cool thanks.

I saw where the board-piece looked like it was some kind of support to be used later but had no idea about this assembly.

Good, I'll do that then.
Thanks again!