Dimple nesting issue from skin to spar

[JDBoston]

Have a feeling this is a basic problem and am curious what people do when they run into this.

In riveting the flap together there is a small gap in at least one portion of the skin to spar mating. It isnt occuring across the whole spar just one section.

Here are a couple of pictures, first where the mating is good:



Here where it is not. Take a look between the rivets on the left more than the clecos.


Top skin was dimpled with a drdt with preloading, and the spar was done with a pneumatic squeezer.
Any ideas?
Thanks

[JonJay]

This is not uncommon. It should help if you amend your rivet sequence. You do not want to start at two ends and meet in the middle. Rivet every other hole, then go back and rivet the others. Start in the middle and work out, or at one end and work towards the other. That small amount of material will then not gather in one spot but will be taken up over the length of the work a bit at a time.

[JDBoston]

Thanks . That is what I will do, it should help. I posted this just as I was starting so very little to undo if any at all.

[rvbuilder2002]

Originally Posted by JonJay

. Start in the middle and work out, or at one end and work towards the other. That small amount of material will then not gather in one spot but will be taken up over the length of the work a bit at a time.

Jon,
I agree it is not an issue but would not agree with starting at one end and working towards the other when there is a situation of slackness in a skin on a control surface.
That is a perfect way to work the slack the entire length and build in a twist in the process.

[JDBoston]

Originally Posted by rvbuilder2002

Jon,
I agree it is not an issue but would not agree with starting at one end and working towards the other when there is a situation of slackness in a skin on a control surface.
That is a perfect way to work the slack the entire length and build in a twist in the process.

Scott,
Merry Christmas. I went back and am starting from the middle working out towards each side, so far so good.

[maniago]

Personally, I don't use the cframe if I can use the hand squeezer instead, especially on any edge. I haven't had the skin expansion issue you show here. That said, I don't have a drdt either - I have a bang and ear-plug cframe - and I hit it with a 4lb hand sledge, though choked way up to the hammer end. Works for me.

[aerhed]

I like to cut nodes to gather slack on sheets. Pin the center with a couple rivets, then a couple rivets just in from each end. Half wave. Then cut those half waves into quarters. At that pointor the next node I just start riveting high spots. Divide and conquer.