Newbie: Reassembling Structures

[MJarreau]

Given:

• 2nd hand kit (-10)
• Vic strongly encouraged us to start on the HS. This is what we are doing.
• We have no major experience using our hands and NO construction experience.

Problem:

We final drilled the skin to the spar/rib assembly and that went well enough. The rear spar was then removed from the assembly because clecos on the final 4 holes were within the structure and had to be removed (this included removing most clecos between the front and rear spar). In reassembling the HS, the holes do not appear to completely align, being fractionally off in most cases.

We expected to be able to reassemble the components and be able to pass a #40 drill through each hole without much difficulty. This is not the case.

Question:

Do we have to somehow finesse the reassembly to make this possible? If so, can you suggest how?

I did a search of the archives but did not find anything along these lines.

Best regards,
Michael

[Mike H]

Sounds normal to me. This type of misalignment is especially evident when working on small radiused bends such as the leading edges of the flight controls, wing leading edges etc. when you start installing rivets the structure will start to line up better. If there is more than a few thousands misalignment you can remove all of the clecos and reposition the skins or parts, then reinstall the clecos starting from the middle working outwards from the middle.

[wirejock]

Hopefully a 10 builder will chime in.
On my 7a, parts go back together with very minimal effort. Except parts in tension like leading edge or tank skins.
Occasionally when several parts have to line up like rib, stiffener and skins, I use a pic to get the holes lined up. Usually after a few clekos are in, all the others line up.
Are you saying even after clekos, the holes are off? Or are the holes off with no clekos? The latter is not unusual but kinds depends on where and bow far off.

[60av8tor]

Hi Michael,

Not sure I'm following your post exactly - you final drilled your HS, removed the spar, reassembled, and now the holes are misaligned..? If this is the case, then I would go with MikeH's suggestion of starting over clecoing from the middle of the structure out. The HS should align easily, but sometimes the order of clecoing will affect things slightly.

[ppilotmike]

It's important to always mark things when they are together to be match drilled. That way you know exactly how they go back together later. I would play around with each part as you reassemble. My bet is that some part is turned around, or switched left for right or top to bottom. Once things are match drilled, they typically do go back together with minimal effort.

[DaveO]

In my build if parts do not align within reason then i had done something wrong. However on the subject at hand a small amount of misalignment is normal.

hang in there it is not that difficult.

Dave

[claycookiemonster]

I strongly second PPilotMike's suggestion. Especially if you're getting into the project with some bits completed, you may not yet appreciate just how subtle the Left/Right or Forward/Aft or Top/Bottom differences are.
On some parts it may not matter until you've drilled them together, on some parts it's different from the start even if it's hard to see; but it's always important to clearly mark all parts with orientation guidance so things get put together the same way everytime.

The hard part is the first clecoed assembly, after that it usually gets much easier.

[WSBuilder]

I will use a few un-driven rivets in every-other hole to index the parts then begin inserting the clecos. Makes a big difference. Even still, you'll end up with some holes that will need to be match drilled again.

[jrs14855]

Originally Posted by WSBuilder

I will use a few un-driven rivets in every-other hole to index the parts then begin inserting the clecos. Makes a big difference. Even still, you'll end up with some holes that will need to be match drilled again.

That is a method used by John Thorp in the 1960's and probably for many years before that.
If you have just one or two holes that do not line up a punch awl inserted into the hole and rotated back and forth will help align the holes and if necessary rotating the awl repeatedly will remove a slight bit of material. Easier than re drilling and less of a burr.

[wjb]

Originally Posted by jrs14855

If you have just one or two holes that do not line up a punch awl inserted into the hole and rotated back and forth will help align the holes and if necessary rotating the awl repeatedly will remove a slight bit of material. Easier than re drilling and less of a burr.

+1 on this; especially if you dimpled the parts after the match drilling A little poke with a awl works great to realign the holes. I was super effective on my wing and fuse skins.