Nicks on wing attach bolts!

ArVeeNiner · #1 05-02-2009, 07:07 PM

This may be a question for Van's but I'll throw it out here.

A couple of years ago I fit checked my wings to the fuselage. I used undersized bolts pretty much but I went ahead and fit checked the real bolts at some point. Frankly, I can't remember doing this but I know I did. I may have fit checked them only into the wing spars.

Anyway, on one bolt, I noticed a small nick. I didn't like that so I thought that I'd replace it someday. Well, I was putting an order in to Van's today and thought I'd look at the rest of the bolts and 5 of the 8 have nicks.

Are these anything to worry about? I guess I could replace them all at $11 a pop just for piece of mind. I looked in the spars themselves and I didn't see any damage in there so I'm not sure how they got this way.

I've lined up the nicks all in a row in the pictures below. Some are hard to see.

Geico266 · #2 05-02-2009, 07:16 PM

They may have come from the manufacturing process.

Mel · #3 05-02-2009, 07:18 PM

They would always be in the back of your mind. This is one place not to take any chances. For the cost of replacement, it's worth it for the piece of mind.
I've rebuilt several wrecked RVs, and wing, empennage, and engine mounting hardware always gets replaced regardless!
Just my $.02.

ArVeeNiner · #4 05-02-2009, 07:50 PM

Yea, that's what I'm thinking. It's one of those things I'll be thinking of at every bump. Sometimes you just have to bit the bullet.

I can't say that the nicks were there before I put them in. I don't remember looking at them that closely. If they weren't there to begin with, it's a mystery to me how they got there.

Oh well.

guy_deraspe · #5 05-03-2009, 10:03 PM

All my wing bolts were also like that.

I believe it comes from handling them: the threads are protected by a plastic sleeve but not the shank; if a vertex of the hexagonal head hit the shank you will get a nick very similar, that is my theory for that.

I wrote to Van's a while ago, I was asking about stress concentration in the bolts if was going to use them, and here is the answer I have got:

"the word from engineering is that small nicks in the bolts don't matter. The spar will fail long before the bolts and the fatigue cracking from stress risers is not much of an issue in steel. The only thing we would recommend is that you smooth any RAISED areas which might scratch the inside of the spar holes when the bolts are inserted."

But my plan is to install new bolts without nicks.

Guy Deraspe

az_gila · #6 05-03-2009, 10:29 PM

Quote:

Originally Posted by Mel

They would always be in the back of your mind. This is one place not to take any chances. For the cost of replacement, it's worth it for the piece of mind.
I've rebuilt several wrecked RVs, and wing, empennage, and engine mounting hardware always gets replaced regardless!
Just my $.02.

...have you seen any damaged bolts in the wing or tail attach in these rebuilds?

Or does the structure fail first?

Mel · #7 05-04-2009, 06:31 AM

Quote:

Originally Posted by az_gila

...have you seen any damaged bolts in the wing or tail attach in these rebuilds?

Or does the structure fail first?

No Gil,
I've never seen bolts damaged by the wreck. I just routinely replace to cover any damage that might have been done during dis-assembly. probably over-kill.

MNAv8or · #8 05-04-2009, 09:26 AM

Quote:

Originally Posted by Mel

I've never seen bolts damaged by the wreck. I just routinely replace to cover any damage that might have been done during dis-assembly. probably over-kill.

I completely agree with Mel here. I am rebuilding a wrecked RV8 right now and it may be over kill, it may not be. But you don't know what kind of stresses may have been introduced to the hardware and it is cheap enough just to replace them with new.

If you don't change them, and if your are like me, every bump you hit your mind will ask yourself if you should have changed them. They will probably be fine if you did put them back in, but peace of mind to me is a huge issue.

BillSchlatterer · #9 09-22-2009, 08:46 PM

I know this thread is old but just for the record, I also ran across similar marks when I made the undersize bolts for test fitting. Normal hardware bolts are between .425 and .430 and the CT bolts are all around .435. The .435 CT bolts would not go into the spar holes by hand. .005 makes a lot of difference.

Using a dial micrometer, I checked three brands of hardware store bolts that were in the bin and got numbers as small as .422 and as large as .435. I found one brand (Zimmer head markings) that were all about .428. Anything around 430 will just fall through the wing spars very nicely. I picked out 10 bolts of the same brand and cut the threads off to make pins. Before cutting off the threads, I chucked them in my drill press and used some 1" wide 180 polishing cloth to polish off any high spots. Once the shine was off, I could see the same kind of marks as in the pictures above. I also notice that you really only see them where the cadium plating has been rubbed off.

I also noticed that even though the test bolts would fall though the spar holes, they would still hang up on the plate on the outside of the spar which means that it is slightly misaligned as noted above. My plan is to ream/remove just the slight misaligned part of the plate and not touch the spar itself.

Same deal on the 1/4 bolts as well.

Just another data point.

Bill S
finishing