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Dimpling mistake?

D

donoltman

Active Member
I may have a problem. On page 6-3 it talks about what not to dimple. I marked the VS-1001 correctly, went about dimpling, (love my DRDT-2) and without reading any further promptly dimpled all of the flange holes on the VS-1004 and 1005. Step 5 says not to dimple the flange holes for the eventual attachment of the fairing. Did I really screw up? Do I need to re-order the 1004 and 1005 or will the fairing still attach properly in the end? I don't mind re-ordering but after reading the fairing attachment at the end of the book it's not really clear to me how the fairing attaches at these flanges. On a lighter note, I am really excited to be starting on Kit #282 which was passed around the country a couple of times before I got it. Other than the plastic being a royal pain to get off it's in good shape.


Don Oltman
 
Eventually the holes in question will get nutplates installed for the screws which fasten the fairing. I would just install countersunk nutplates instead of the ones which are specified (K-1100-xx instead of K-1000-xx). Of course there will be no metal directly below the screw head behind the fiberglass so you won't want to over-tighten. If you see the fiberglass fairing starting to bow into the dimple, stop and loosen the screw a turn or two.

Alternatively you can gently pound out the dimple with a rubber mallet. This will weaken the aluminum there, but since the nutplate will carry the load outboard of the hole I think this is okay.
 
Short answer: I'd squeeze them flat and build on.

Long answer: Going from flat->dimpled->flat->dimpled-the-other-way is okay in many instances. Any more than that and fatigue cracking is likely; but in your case you'll be just fine in making them flat.

-Jim
 
dimpling

Bob;

Thankyou for the countersunk nutplate option. The good news is that I didn't dimple the VS skin so there will be metal directly in behind the fairing albeit not as solid since the flange is dimpled. I'm not excited about pounding out the dimple because I think it would be very difficult to inspect later on. Think I'll change to countersunk nutplates.

Don
 
Go use a flush set in your squeezer and see how simple

..it is. The dimple returns to flat very nicely. Wouldn't you still increase the nut plate hole for the correct fastener diameter later? I wouldn't pound it with a rubber mallet. the flush rivet set works really well and I believe Vans has said in the past you could do that procedure . Just don't over squeeze it. Ymmv.
 
dimpling

Good idea. I have a scrap piece with a dimple that I'll try that on tomorrow. That would really make it easy.
Don
 
Not only that but the load won't be on the hole you've dimpled and flattened. It will be on the nutplate behind it. So as long as the hole is smooth and there are no cracks, you are fine. It would even be ok to open up the holes a bit (better to drill for the nutplate rivets first) if you need to in order to remove any edge nicks.
 
Flatten out the dimple you don't want. As long as there are no cracks around the edge of the hole you are fine. You may want to drill the hole to the next number size out to be sure the hole remains smooth inside. When you install the nutplate you will be drilling the hole out anyway.
 
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