Michael Burbidge

Michael Burbidge

Well Known Member
I'm going to use k1000-06 nutplates and AN507-6R6 screws to attach the fiberglass wingtips to the wing skins.

I wasn't thinking and got a little bit ahead of myself. I drilled the skins out to the fullsize using a 28 number drill and then dimpled, before match drilling the fiberglass tips to the pre-punched hole.

I got focused on how I was going to dimple the skins because they are so close to the ribs that I didn't think ahead.

Anyway, now I'm not sure how I'm going to match drill the fiberglass tips to the dimpled holes, since dimpled holes are usually slightly bigger than the drilled hole.

I see three options.

1) Someone gives me a suggestion as to how to match drill using the dimpled holes. Maybe it won't even be that hard to get the hole close enough to center.

2) Flatten the dimpled skins using flat dies in my squeezer. Then match drill and re-dimple. Would I have to worry about metal fatigue?

3) Flatten the dimples as above and then drill new holes in the middle of the existing ones. Then use these new holes to attach the wing tips and fill in the original holes when painting.

I don't really like option 3. It just looks bad, while building. It will bug me every time I look at them.

Any suggestions?
 
Guidance

Your post was timely. I'm completing a multi part guide on mounting your tips.
I hope to have it done this weekend and will post it here.

Drilling to final size is the last thing you do:(
 
Measure the ID of the dimpled holes.

Go to McMaster-Carr on-line and buy a drill bushing as close to the OD as you can get with say a 1/8" or #40 ID.

Tape or otherwise secure the wing tip in place.

Make sure that it is very snug at the leading edge.

Using the drill bushing drill 4 holes at the quarter points on the top and bottom surfaces.

Remove tips, open up holes and install the nut plates.

Re-attach the wing tips with #6 screws and then drill the other holes - or at least every other hole using the drill bushing.

Open up as above and install nut plates.

Re-attach and drill any remaining holes using the bushing.

Not the easiest but it's an option to get back to where you would have been.

The tips are "floppy" until fully attached so you need to "fix" them in stages and make sure that they are "snug" where needed - especially at the leading edge ore nose.

Jim Sharkey
 
I would just flatten out the dimples. As long as the holes are deburred you wont cause any cracking. Obviously not ideal, but simple.

If you try to drill through the dimple you be off a bit. and that'll be frustrating. You could drill through with a 1/16th drill bit and gradually work the hole size and center up and in a alignment.
 
Flattening dimples was my downfall

I tried to flatten dimples once and found that cracking isn't the only hazard. You stretch the metal and once it is stretched out and wider, you can't just stuff in back from whence it came. I ended up with a mess and replaced the part. Hope you have better luck than I did if you try it.
 
I don't hav a picture to go by but you could

1. You could use a strap duplicator.

2. Transfer pins

3 use a sharpie and draw 2 lines 45 degrees from each othe and the intersect over the center of the hole. place the wing tip on and then (use a straight edge to continue the lines on the wing tip untill they once again intersect. Redrill and then use floating nut plates
 
Or ... you could just ignore the problem and it will go away. Kidding? Nope. You're going to put a nutplate behind those holes anyway. Drilling them out oversized won't hurt a thing. When you go to install the nutplates, use one that has been tapped out (easier to run the screw) as a jig; run a screw through it and the screw will center the nutplate in the oversized hole. Now drill the attachment holes and you're done. Someone mentioned how floppy the tip is; I'd start drilling at the leading edge and work back to the trailing edge.
 
Drilling the wingtips

Find another builder in your area and ask him if you could use his wings to drill your wingtips. That would be easy in the DFW metroplex. Hopefully, there are other builders near you.
 
I like the last idea with finding another RV to at least mark your holes with, but otherwise I would do option 2 and re-flatten the holes. I have re-flattened a few accidentally dimpled holes without consequence.
 
Or... do what the certified...

flion said:
Or ... you could just ignore the problem and it will go away. Kidding? Nope. You're going to put a nutplate behind those holes anyway. Drilling them out oversized won't hurt a thing. When you go to install the nutplates, use one that has been tapped out (easier to run the screw) as a jig; run a screw through it and the screw will center the nutplate in the oversized hole. Now drill the attachment holes and you're done. Someone mentioned how floppy the tip is; I'd start drilling at the leading edge and work back to the trailing edge.
Click to expand...

...planes do in this same location and use floating nutplates.

fmNoseNutPlate.jpg


This way you don't need the precise alignment accuracy of the holes in the glass tip, and nothing will move when all of the screws are tightened.

A slight variation on Patrick's suggestion above.

Unlike the certified manufacturers, homebuilders usually have more precise alignment of parts and tend not to use/need the tolerance of the floating nutplates....:)
 
Installing my wing tips this week

RV7Guy said:
Your post was timely. I'm completing a multi part guide on mounting your tips.
I hope to have it done this weekend and will post it here.

Drilling to final size is the last thing you do:(
Click to expand...


Hey Darwin,

If you have a draft copy of you guide I sure would appreciate a sneak peak. I will be working on the tips Friday thru ??

Thanks,
 
Maybe ,.... a spinning drillstop or a male dimple die?

Michael, you might try taking a #30 drillstop, the kind with the spring in the middle and set the bit in the chuck so that it barely sticks out of the end. Don't lock the drill stop in place so that the drill will spin freely.

Now just center the drill stop in the dimple, start the drill and press just hard enough to compress the drill stop to the point that the bit just goes through the fiberglass or at least gives you a starter hole. That should give you a centered #30 hole.

Then drill the #30 out to #6 size and use a nutplate jig or nutplate/screw to final drill the nutplate to the wing tip.

Check to make sure the spinning of the drillstop doesn't mess up your wing dimple. You probably should try this on a piece of scrap first.

>>>>>

Another thought might be to take a set of #6 nail dimple dies and just use the male side as a drill guide. Use whatever drill size fits in place of the nail. I "think" it should center in the dimple and give you a centered hole in the wing tip. Then drill out to #6 nutplate. Now that I think about it, I might try that first.


Just a couple of options ?

Bill S
7a finishing
 
I'd probably try making a template of the outboard 3" of the wing out of some scrap .016 aluminum or something similar.

Put your template outside the wing. Then align the edge of the template with the outboard edge of the wing and clamp it into position.

The next step is to get your holes transfered onto the template. If it were me, I'd find a drill bit that fits the dimpled #28 holes tightly. Insert that drill bit into the back side of the dimple and push it against your template. Twirl the bit in your fingers and it will mark the center of the hole on your aluminum template. Since the drill bit fit tightly, you know you're as close to perfect as you'll probably get. Now that you have your template holes marked, you can remove it from the wing and drill them.

Then transfer your template to the wingtip.

I think that'll put you right on. If not, then you're going to be really close and repairing the FG wouldn't be that difficult. But I bet you wouldn't need it.
 
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Hinge bit

There is a kind of drillbit available at home improvement stores called a "Hinge bit". It's kind of like a drill stop and drill bit all combined into one. They're used when drilling door hinges to a door frame, but do a reasonably good job of centering the drill on the dimpled hole. Hope that helps!

20070324-34-tn.jpg
 
They make a tool for this

It is called a transfer punch:

http://en.wikipedia.org/wiki/Punch_(metalworking)
"A transfer punch is a punch (usually in an index set) of a specific outer diameter that is non-tapered and extends the entire length of the punch (except for the tip). It is used to tightly fit the tolerances of an existing hole and, when struck, precisely transfer the center of that hole to another surface. It can be used, for example, to duplicate the hole patterns in a part, or precisely set locations for threaded holes (created by drilling and tapping) to bolt an object to a surface.

Photo: http://www.buildlog.net/cnc_laser/images/transfer_punch.gif

Invaluable for building an RV when you inevitably do something out of sequence...
 
You might consider doing it hole-by-hole, that is, drill the most forward hole or two, take the tip off, c-sink and fit nutplates, then do a couple more, etc.

That might help keep things in the right location fore-and-aft...dunno. Just thinking out loud.
 
Hinge bit worked great

Thanks for all the suggestions. I picked up a $5 hinge bit from Home Depot. It worked great. Every hole was very nicely centered. It was no big deal. The first wing tip ended up fitting almost perfect using this approach.
 
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