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Drilling W-408 and Joint plate in Leading Edge

KMinor

Active Member
This has been the hardest part for me so far. I just reordered the ribs and joint plate for the second time. The first time I measured the exposed joint plate to 11/16" from both the edge of the skin and the web of the rib and started drilling. On both ribs the holes started showing up too close to the web so I stopped and reordered. The second time I marked a line on the flange of the rib, placed it inside the leading edge, used a punch to mark one bottom hole, took the rib out, drilled the hole, measured and drilled the equivalent hole on the joint plate, then clecoed it all into the leading edge to help with alignment. This worked fine on the that side, but when I started measuring and drilling the other side I got too close to the web again. Must have been poor alignment when drilling the rib flange to the spar. Anyway, I'm about to lose my mind with this. Anybody have any tricks to share?
 
KMinor,
Hang tough buddy!
I had to park my project about 10 days ago, but that was the last step I completed before I did.
I'm at the Fire House tonight or else I would go out in the garage and re-do some pics of how I did mine. It was really easy, but I'm not to proud to tell you that I do a lot of stealing ideas from others build sites.
Let me try to walk you through what I did from memory and a couple pics I took along the way.

1) I gently held the the rib in the vise and marked the center of the flange all the way around.

2) I stuck the rib in the skin and marked on the flanges through all the holes in the skin with a sharpie so I knew where the holes will be on the rib flange allowing me to know where to flute (in between the holes) to get the rib to lye flat.

3) I fluted the rib flat.

4) I put the rib back in the skin where it will live the rest of it's life and secured it down flush with the edge of the skin the best I could with the tools I have available.
You can look through the skin holes at this point and have confidence that with the line you drew on the center of the flange lined up with the holes, the rib web should be pretty close to flush with the edge of the skin. And that's the last time you'll see that line until after all the holes are drilled in the rib.
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Here's where you got to look at your call out manual for the sequence. I don't have mine with me, but I think I
5) back drilled the aft flange through the spar at this point.

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That makes sense cause on the next pic above I removed all that clamping mess.

6) Next I clamped the joint plate to the skin by wedging one jaw of the cleco clamp in between the skin and rib with the other jaw holding the joint plate to the outside of the skin. I did this with a few clamps as seen in the pic. This is to pre-form the bend in the joint plate.

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I just rubbed my hand right around the leading edge folding the joint plate around with it, being careful that it didn't make a crazy turn away from the edge of the skin. The first time I ended up with excess joint plate close the the spar and not enough plate at the other end. It was easy to manipulate the plate to make up the difference and have it come out with the same on both ends of the plate (this must sound confusing but trust me it was easy).

I unclamped the plate and inserted it between the rib and skin, just as the call out directs us to do. I didn't even need a soft mallet, I just bumped it with the palm of my hand as needed as I went around the rib.
Yes the rib moved all over the place, but the clecos through the spar held the aft end of the rib in place.

7) Ok, I used my steel ruler and marked the 11/16" (I'm using that figure off your post cause I don't remember what it was in the book) point on the ruler with the sharpie.
I started with the aft bottom hole. I measured the edge of the skin to the edge of the joint plate, then measured the web of the rib to the edge of the joint plate.

8) When I had 11/16" from the edge of the joint plate to both edge of skin, and rib web, I drilled the first hole.:eek:
Having that first hole cleco'd made the rest of the run comforting to me. I measured and drilled the next two holes.

9) Then I moved to the top of the leading edge and repeated starting at the hole closest to the spar working towards the leading edge.
At this point I had 3 holes drilled and cleco'd on the bottom, and 3 on the top.

10) From there I would do 3 or 4 on one side, then repeat on the other working my way towards the leading edge.
I used my steel ruler and measured every single hole all the way. The joint plate seemed to stay in place pretty well, but the rib tended to want to wander a bit.
I grabbed the rib through one of the two lightening holes and forced it as hard as it would take then drill to have that 11/16" distance work out on each hole. If you let that distance wander too far, it takes a lot of force and a couple holes to get it back, and in the mean time your having edge distance issues on the rib that are not visible to you at the time.
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In hind sight, you don't even need to draw that center line on the rib flange, cause when the drill hits the metal you can't see it anyway.
The key to this operation is that 11/16" measurement. If you got it on both sides of the joint plate (rib & LE skin) your money.;)
This is very wordy I know. But I hope it helps you out.
We got to get these wings done. They're so boring (however I'm loving it!).

Good Luck friend.
Tom
 
Thanks Pal!

I appreciate every word of it. I especially like your clamping rig at the start. I think that will help keep that aft flange lined up straight to begin with. I might need to be more diligent after I get the 11/16 measurement on both sides to make sure I'm not letting the drill bit move the rib as it goes through. Thanks for the reassurance! I looked at some builder sites but didn't find this kind of detail. Now to wait for a week for the parts! Thanks again!
 
Finally!

I think I finally cracked the code on this for my purposes. I clamped it all down as suggested above to get the bottom rib flange square and drilled. Instead of counting on the 11/16 measurement on both sides of the joint plate, I predrilled the holes in the joint plate without drilling all the way through. Then I pulled that portion of the joint plate out, held a block of wood behind it, and drilled the holes through. Then I lined the joint plate back up with the blue line that then became visible on the rib flange, through the skin and joint plate holes, and drilled through the rib flange. They all came out centered. Maybe it's just me, but the joint plate overhang measurement is about 11/16 on the skin side, but is about 1/16 less (so 5/8) on the rib side. At least the holes are where I want them!
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My thanks to both of you...

.....For posting this information. I have managed to find myself in this very same predicament, and don't ya know that since I decided to build both wings at the roughly the same time I managed to screw up both 408 ribs. I should have done my homework better, because I just knew that the wings were coming together way too well for this to continue for very much longer.

I will be using a combination of both of your methods - ensuring the rear flange is straight when it gets drilled, and predrilling the W423 joiner strip to expose the line that I will also draw on the rib flanges. In fact, my joiner plates are already "predrilled," but it looks like the holes wandered a bit on one of them, so I may have to make and predrill a new one.

There is one other aspect of all this I would like to call attention to. From the plans that I have reviewed, it seems that there is still a nice gap between both the outboard tank rib and in the inboard LE rib - enough to not really have to worry about this whole 11/16 of an inch business.

So Kminor, as you have pointed out, the rib seems to need to stick out a bit further in order to keep the top and bottom rib flange to wing skin holes in the correct position. That was my observation as well. So, since I know there is a gap between the two ribs involved in this whole "joint" process that should allow for some leeway, and I also know that the rib web to end of joiner strip measurement will most likely be somewhat less than 11/16 of an inch, I am also much less concerned about the 11/16 measurement and more concerned with the method to align all of the parts, i.e. lines on the flanges and creating the ability to see them by exposing each layer of metal, one at a time.

I have not been happy at all with Vans instructions for the wing assembly, and frankly I'll be glad when the wings are done so that I don't have to deal with another leading rib again. Thanks to you and a few others for shedding some light on how to properly complete this ridiculously complicated process. I will be thoroughly documenting everything I do in my blog.
 
Homework

If you don't like the instructions for the wings, you're really in for a disappointment on the fuselage...:eek:

Thus the reason why adequate time spent doing the homework where on VAF is so important. I rely heavily on guys like you Miles to keep me going down the right track. The left wing joiner/rib re-do worked out pretty well yesterday. Will work on the right wing assembly tonight.

Need to get back into my routine of researching first and drilling later. I should have realized it was time to do more research when I got to the point of utter disbelief that they really wanted me to assemble 3 pieces of essentially unclamped metal together, magically align everything just right, and then start drilling holes, and hope that the alignment of all 3 parts would remain in tact. Lesson learned....

Someone told me that the fuse instructions were better than the wings, so I was disappointed to hear you say that they are not that great. In any event, I am fairly certain I will enjoy working on structures that don't involve a rib assembly. Fuel tanks coming so I am certainly not there yet...
 
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