Section 10 Question

This question is for those that have the 14 empennage kit, but have not yet started section 10, the Aft Fuselage.
I am in the initial stages of section 10 for my 14A project. On page 10-09, step 1, it says to "Final-Drill #30 the hole locations as shown in figure 1". These #30 holes are final drilled through two bulkheads and the Horizontal Stab Attach Bars. Easy enough. However, after clecoing the parts together and getting ready to final drill these holes, I noticed that it appeared the holes in the horizontal stab attach bars were already larger than a #30 bit. I un-clecoed the parts to investigate and discovered the holes on one side of the HS attach bars were larger than the other. This was the same for both HS attach bars. The larger holes on the one side made for a "sloppy" fit for a #4 rivet, while the holes on the opposite side the rivet would not even fit in the hole (not final drilled#30 yet).

This picture shows the parts I'm referring to.

This is the side of the HS attach bar with the enlarged hole and sloppy rivet fit.

This is how far the rivet makes it through the HS attach bar as viewed from the "small hole side".

This is the rivet on the "small hole side". The rivet does not even penetrate the hole (as it shouldn't since not final drill yet), I just have it balanced on top of the hole.

My question is for those that have the Horizontal Stab Attach Bars (F-01411C), but have not yet final drilled to #30. If you could check to see if yours have the same "enlarged" holes on one side as mine do.
The enlarged holes are "probably" ok. I don't love it , but just wanted to check before I decide what I'm going to do.
Thanks..., and sorry for the large pictures.

Ditto what you said - mine are the same. I don't know if the existing oversize hole is too large to fill when the rivet expands, though. Haven't reached that step yet.

I can just get a #26 drill (0.1470") in the enlarged hole.

Maximum hole size for a 1/8" rivet is given as 0.135" here:
http://www.engineersedge.com/rivet_application.htm

MED said:

Ditto what you said - mine are the same. I don't think the existing oversize hole is too large to fill when the rivet expands, though. My opinion only. Haven't reached that step yet.

I can just get a #26 drill (0.1470") in the enlarged hole.

Maximim hole size for a 1/8" rivet is given as 0.135" here:
http://www.engineersedge.com/rivet_application.htm

Click to expand...

Thanks for the reply and info. I had checked that mil spec document as well. I measured the "enlarged" holes at 9/64" (0.141"). Technically..slightly over sized I guess.
I may check with Van's just to see what they say and also find out why/how the holes are being formed that way.

Please post what Van's says. I am currently working on the elevator, so I will reach section 10 soon and others likely have the same issue.

Will do

MED said:

Please post what Van's says. I am currently working on the elevator, so I will reach section 10 soon and others likely have the same issue.

Click to expand...

I sent Vans an email this morning. I will let you know.

Hole Measurements

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This is the "large" hole side of the brackets.

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This is the "small" hole side of the bracket.

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Page from Mil Spec manual showing hole diameter limits.

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Thanks for highlighting this issue. I'm not quite this far along yet and I'll need to check my kit for this problem as well. Could you highlight your builder number as that might help us isolate the problem to some specific kits. (I'm #294) My previous experience in a precision sheet metal shop suggests that the problem is likely due to the punch and die not being correctly set up. The "top side" punch was the correct size, but the "bottom side" die was oversized. This leads to an inverse funnel shaped hole! with a good hole on the top surface and the bottom gets broken out to the larger hole diameter of the die. Even in your pictures, the "bottom" hole appears to look a little ragged. I'm looking forward to what Vans has to say...

YoVuelo said:

Thanks for highlighting this issue. I'm not quite this far along yet and I'll need to check my kit for this problem as well. Could you highlight your builder number as that might help us isolate the problem to some specific kits. (I'm #294) My previous experience in a precision sheet metal shop suggests that the problem is likely due to the punch and die not being correctly set up. The "top side" punch was the correct size, but the "bottom side" die was oversized. This leads to an inverse funnel shaped hole! with a good hole on the top surface and the bottom gets broken out to the larger hole diameter of the die. Even in your pictures, the "bottom" hole appears to look a little ragged. I'm looking forward to what Vans has to say...

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My kit number is 174. Thanks for the explanation on how the holes were possibly formed this way. I was curious how that could happen.

Vans Reply

I got a call this morning from Sterling at Vans. He indicated they have heard this before with some of the Horizontal Stab Attach Bars (F-01411C). He said the issue was researched and even several experiments with riveting these parts were conducted. He said there should be no issue with the parts as is. However, he indicated that, if possible, place the shop head of the rivet on the "large" hole side of the HS Stab Attach Bar so the rivet will have a better opportunity to "swell" and fill the hole.
He also indicated that the "newer" version of these parts possibly have better formed holes. I did not ask about when (kit #'s) the "newer" parts were included in the shipped kits. Probably tough to determine anyway.
I had considered upsizing the rivets for these holes to #5. I mentioned that to Sterling, but he felt that was probably overkill and not necessary.
I ended up ordering new parts. I will advise when they show up as to any differences.

You don't final dril those holes yet

The three larger holes are drilled later for a bolt (#4) I think. The larger holes are for the top of the strap

Thanks for checking with Van's. How much were the replacement parts? Like you, I may just replace them, depending on whether you think they are better. Please let us know what you get.
By-the-way, I have kit #236.

Same here with kit #152. I am STILL finishing the wings and will move on to this portion shortly so I am interested in what you find. I am yet to study the plans here though to understand where this fits in.

Parts

MED said:

Thanks for checking with Van's. How much were the replacement parts? Like you, I may just replace them, depending on whether you think they are better. Please let us know what you get.
By-the-way, I have kit #236.

Click to expand...

The replacement parts were $11/ea. Little more than I was expecting.
I will post the results when I receive the new parts.

Why are these not recognized as defective parts and replaced for free?

Incidentally, and curiously, the similar F01410 bars in my kit are drilled/punched perfectly.

Replacement Parts

I received the replacement Horizontal Stab Attach Bars today that I ordered from Vans.
The holes in the replacement parts are perfectly sized (both sides).
Here's the new parts.
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Thanks for that. I guess I will be calling Van's this morning.

I also have the attach bars with the over sized holes, kit 180.

When attempting to replace them (F-01411C), I was unable to find the parts at Vans and am waiting to hear back from them.

Looks like F-01410 has replaced the original part. Can any of you confirm that?

Thanks,

Just call Van's and tell them the part number you need. I ordered replacements for the 01411s because the holes in the ones supplied with my kit were oversized. I am happy with the the replacements. The 01410 parts are not the same part. They are shorter and mine were punched properly.

Hey thanks,

Just found the two F01410C in my kit... you're right different parts. I'll wait another day to hear back from Vans then call.