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Match drilling dimpled skins to new non-dimpled spar/ribs

Clarkie

Well Known Member
So now that I have admitted defeat and ordered a new HS front spar and 2 new ribs, how hard is it going to be to match drill the already dimpled skin to the new spar? Part of the spar isn't pre-punched and you use the skin as guide. Any suggestions?
 
I've done this on several occasions. Just cleco what you can together, drill the holes straight, cleco as you go and call it good. Remember, you are not building a swiss watch...you are building a tractor.
 
Tom you could try a spring pin or something similar from your local hardware store. I used on when I remade my splice plate between fuel tank and leading edge. It fit perfectly inside the dimple and allowed me to have the pilot hole in the new piece centered in the dimple. I then drilled it to full size. Worked great for me.
 
Since I haven't built a -7 is the spar already matched drilled to accept the skins? If so, given the precision of the match drilled holes, I personally would just ream the holes in the spar to a 40 and countersink/dimple the spar as per the plans. Any holes not prepunched should be easy to center up the drill and match drill them. Just my own 2 pennies.
 
Good advice....

I've done this on several occasions. Just cleco what you can together, drill the holes straight, cleco as you go and call it good. Remember, you are not building a swiss watch...you are building a tractor.

Ditto what Aaron said. I had to do this not too long ago for the forward spar of my left elevator. If the new HS forward spar does not have predrilled holes, that is fine because you just use the dimpled holes in the skin and match drill new holes in the spar.

If the spar does have pre-drilled holes then I also found this to be a non-issue after clecoeing and drilling through the dimples. It does make things look a little "off" when you try to cleco the dimpled skin to the non-dimpled spar and ribs. I had that same uneasy feeling when I did mine. Just try to put it out of your mind. :)

Drill straight and cleco as you go are very important points. In fact, I would cleco every hole instead of every other hole if you are concerned about alignment. I found that after I redrilled the holes and set the dimples in the spar that the skin sat right down on the frame as if nothing had ever happened.

Build on!
 
Thanks for all the responses guys. My nerves have calmed down quite a bit after taking a few days off! Ready to get at it as soon as the parts arrive. Sure do wish Van's had a parts distribution facility on the east coast somewhere. Waiting and waiting for parts is torture.
 
start the VS

I started my VS whie waiting for HS replacement parts...
Always lots to do.
You could also de-burr everything in sight!
Happy building.
 
Strap Duplicators Maybe?

You may want to look at this useful little device which enables a hole to be match drilled accurately. I am not sure if the dimple will affect accuracy so take care. I know that some of the "Gurus" have recommended these in past posts on VAF. However mayby I am talking total rubbish so treat this with care.


Strap Duplicators


Strap-Duplicator1.jpg
 
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