Messed up HS Front Spar During Assembly. How to redrill?

[Echo Tango]

Long story short, a botched rivet removal led to a "size up" rivet solution which led to a fairly idiotic mistake of using the wrong dimple die on my HS front spar and the sheet tore/cracked.

My question is this: since my HS skin is already final-drilled and dimpled, how do i match drill my new spar? I feel like I might enlarge quite a number of holes trying to match-drill a dimpled sheet to an un-dimpled spar. I don't think my dimple dies will fit the undersized "virgin" holes provided by Vans, so that's probably out of the question as well.

Should I just use my #40 drill on the spar, dimple it and hope for the best? I'm fairly certain this will work, as i've never really had any holes that were very "off" coming from vans... everything seemed to match up near perfectly.

Oh, it's an RV-7

[Don Jones]

Originally Posted by Echo Tango

Long story short, a botched rivet removal led to a "size up" rivet solution which led to a fairly idiotic mistake of using the wrong dimple die on my HS front spar and the sheet tore/cracked.

My question is this: since my HS skin is already final-drilled and dimpled, how do i match drill my new spar? I feel like I might enlarge quite a number of holes trying to match-drill a dimpled sheet to an un-dimpled spar. I don't think my dimple dies will fit the undersized "virgin" holes provided by Vans, so that's probably out of the question as well.

Should I just use my #40 drill on the spar, dimple it and hope for the best? I'm fairly certain this will work, as i've never really had any holes that were very "off" coming from vans... everything seemed to match up near perfectly.

Oh, it's an RV-7

Just skip the match drill and enlarge the holes in the new spar, deburr, dimple and install, it will work fine.

[Echo Tango]

Originally Posted by Don Jones

Just skip the match drill and enlarge the holes in the new spar, deburr, dimple and install, it will work fine.

thank you

i just wanted some feedback before i moved forward. seemed to make sense in my head, but i'm very apprehensive about "going out on a limb" when i have little experience and a shiny new part is at stake.

[Snowflake]

You should be able to cleco your skin to your spar even if it's dimpled and the spar isn't. At least, the row of rivets where you made this boo-boo can probably be clecoed in place?

If it can, then just use the dimpled hole in the skin to pilot the new larger hole in the spar. That should be close enough. You'll want to be sure that you don't leave behind any "tear" or "crack" though. Those words worry me...

[Flyin'Bryan]

Originally Posted by Snowflake

You should be able to cleco your skin to your spar even if it's dimpled and the spar isn't. At least, the row of rivets where you made this boo-boo can probably be clecoed in place?

If it can, then just use the dimpled hole in the skin to pilot the new larger hole in the spar. That should be close enough. You'll want to be sure that you don't leave behind any "tear" or "crack" though. Those words worry me...

I agree with Rob. Was it your skin or the spar that got cracked? Either way, if a crack was formed, then that is indeed a concern. if you had a picture it would help clarify the problem I guess, but it sounds like you damaged the spar and got a new one, and that the skin is apparently undamaged, is that corrrect? As for the question about match drilling the holes from a dimpled skin onto a non-dimpled/non-match drilled substructure (spar), I agree that it can be done by either method indicated by the previous posters.

I actually had to do this after replacing a botched elevator spar I believe, and I did it the way that Rob suggests. if you are concerned about proper alignment, as long as you cleco all the holes you should have no problems with the fit of the skin to the spar. I clecoed every single hole just to try to ensure that the alignment was as correct as I could make it. Then I match drilled the holes and dimpled the spar as usual. I was just as concerned as you are about the alignment and fit. I was a little awkward with the dimplaed skin on top of the undimpled spar, but as long as you keep your drill 90 degrees to the holes, you should have no problems. In my case everything fit together like a glove when it was all done.

Tell us more about this crack....

[Echo Tango]

Originally Posted by Flyin'Bryan

I agree with Rob. Was it your skin or the spar that got cracked? Either way, if a crack was formed, then that is indeed a concern. if you had a picture it would help clarify the problem I guess, but it sounds like you damaged the spar and got a new one, and that the skin is apparently undamaged, is that corrrect? As for the question about match drilling the holes from a dimpled skin onto a non-dimpled/non-match drilled substructure (spar), I agree that it can be done by either method indicated by the previous posters.

I actually had to do this after replacing a botched elevator spar I believe, and I did it the way that Rob suggests. if you are concerned about proper alignment, as long as you cleco all the holes you should have no problems with the fit of the skin to the spar. I clecoed every single hole just to try to ensure that the alignment was as correct as I could make it. Then I match drilled the holes and dimpled the spar as usual. I was just as concerned as you are about the alignment and fit. I was a little awkward with the dimplaed skin on top of the undimpled spar, but as long as you keep your drill 90 degrees to the holes, you should have no problems. In my case everything fit together like a glove when it was all done.

Tell us more about this crack....

im only re-drilling because i decided to replace the part due to the crack. i finished the new spar today and it's ready for primer. should be able to finish up the HS this week

everything fit together fairly well, and i just match-drilled the holes that weren't in the spar yet, and simply widened the ones that came pre-drilled to their final size without "match-drilling." there were some hairy areas i was worried about where three sheets (rib,spar,skin) came together along with some of the angle stiffeners, but it ended up being fairly easy. took about 2 hours to go from new part --> ready to paint.

thanks for the help, guys!

[Echo Tango]

and yes, i use every dang cleco i own before i drilled


sidenote: need more clecos