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Fuselage Bearing Bracket Misalignment

TASEsq

Well Known Member
Patron
I have prepped the pairs of fuselage bearing brackets including clecoing together and dressing the edges of each pair to remove the stamping marks etc and so they align.

Cleco’d together without the bearing itself, all the rivet holes align and the edges match.

When I put the bearing in place however, the bearing causes a misalignment. Seems there is some out of tolerance between the rivet hole locations and the milled out recess for the bearing. So much so that with the centreline rivet / screws in place I can’t get a AD3 rivet in the outermost hole at all.

You can see there is so much misalignment on one pair I can’t get a rivet in. I’m not totally sure how to handle this - I could potentially ream the #40 holes out to #30 but I don’t think I would have edge distance and it doesn’t solve the misalignment of the holes which are already #30.

Can I sand some material off the edges of the bearings themselves or do they have to fit snugly in the recesses to prevent spinning etc? I feel like they are clamped on their faces more so than held by their perimeter.

In the photo attached you can see how much misalignment there is. I put some blue marker on the inside surfaces of the parts. You can see with no bearing in place that the bearing recesses are not aligned with each other when the rivet holes are aligned.
 

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I think it would be worth replacing those parts, I don't see how they can be fixed in the field because the recesses for the bearings should really be properly aligned to hold the bearing, IMHO.
Have you tried contacting Vans support? If it is a manufacturing defect they may already know about it.
 
I spoke to Sterling back in May about these same brackets. My issue was the bearing offset slightly in the recess. At the time, he had a set on his desk because of another builder having issues. Mine were “within serviceable limits” but he did say that some that he pulled from stock to compare “would definitely not work”. I would talk to Vans support (Sterling, as he is familiar with the issue) and ensure the replacements they send are checked thoroughly before shipping. Keep an eye on the double flush rivets, the ones called out are too long. Also, if priming, clean any primer out of recess as it could cause bearing to sit proud.
Cheers,
Todd
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I had the exact same issue. Sterling told me that reaming out the holes would be fine here.
 

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I happened to assemble this part just 2 days ago and found this same issue.

I riveted the 426-3 rivets (double flush) around the bearing and made sure the bearing still moved freely. I think checked each remaining hole with a 426-4 rivet. Those that aligned (meaning I did not have to force the rivet) have a cleco in the picture - open holes would not take a rivet. I ran a #30 reamer through the open holes and then riveted all. The amount of misalignment was much less than the 1/4 hole reported - perhaps 1/8 max.
 

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I happened to assemble this part just 2 days ago and found this same issue.

I riveted the 426-3 rivets (double flush) around the bearing and made sure the bearing still moved freely. I think checked each remaining hole with a 426-4 rivet. Those that aligned (meaning I did not have to force the rivet) have a cleco in the picture - open holes would not take a rivet. I ran a #30 reamer through the open holes and then riveted all. The amount of misalignment was much less than the 1/4 hole reported - perhaps 1/8 max.

Yours look much better aligned than mine were. I had to run a reamer through all the holes to get a rivet through them. The leaves the two halves visibly misaligned once clecoed.
 
Please let us know what they say. Curious if it will be the same answer I got.

“These parts have always had a slight mismatch. Most builders utilize the furthest bolt location, capture the bearing, cleco as best you can, match drill and assemble.

Interesting to note the engineering manufacturing drawing counterbore depth tolerance is +.005”, -.000” but the rest of the drawing allows tolerances up to .025”!”

I copied Sterling into my reply to get his take on it - but 1/4 out of tolerance seems too much to me to match drill. But I didn’t design it.
 
“These parts have always had a slight mismatch. Most builders utilize the furthest bolt location, capture the bearing, cleco as best you can, match drill and assemble.

Interesting to note the engineering manufacturing drawing counterbore depth tolerance is +.005”, -.000” but the rest of the drawing allows tolerances up to .025”!”

I copied Sterling into my reply to get his take on it - but 1/4 out of tolerance seems too much to me to match drill. But I didn’t design it.

Interesting. Seems like if these parts have always had a slight mismatch, maybe it's time to redo the CNC design to fix it. Curious that only one side is mismatched. I wonder if it's always the same side?
 
So the latest from Van’s - they have offered to send me some new parts but can’t guarantee they will be any better. :eek:

They can’t check their on shelf stocked brackets because they have zero stock of the bearings! Apparently the manufacturer of the bearings can’t get the materials to manufacture the bearings, so vans may not be able to get any!

So I don’t know what the story is here for kits going forward or if I ever needed a new bearing.

Maybe they need to redesign the bracket around a new bearing that has more availability and solve this misalignment issue.

So I am basically stuck with a pair of brackets that I can’t get a rivet in. I guess I’ll just have to ream them and accept oblong holes?

It’s rather annoying because for the rest of the kit so far I have not accepted parts like this. When I’ve stuffed them up I’ve ordered new ones. In this case I am forced to accept misaligned parts which is frustrating. I’m not sure why support doesn’t feel this is as big an issue as I do??

Best I can hope for I guess is that the bearing doesn’t bind when it’s riveted and accept the misalignment of the bracket halves and oblong holes.

I guess I need to re-file the edges of the pieces so they are matched in size with each other the bearing in place?? Does it matter that the pieces are misaligned? These are the elevator stops so I assume the elevator bracket has to contact both bracket halves? As it stands, it would contact only one half of the bracket.
 
MYO?

The bracket halves look relatively straightforward to make, apart from the counter-bored recess for the bearing. If you can get a piece of the correct material (likely .125 2024-T3) and have the recess counter-bored then it would otherwise be simple to cut out and match-drill a new bracket half.
 
If it was me I’d drill (or ream) the 40s out to 30s - rivet and move on.
If you are concerned about edge distance or upsizing dosent solve the misalignment then put some more rivets in.
 
Can you assemble the bearing in the brackets, then use cleko side clamps to hold it together and have all the rivet holes share some misalignment instead of a few gross out of alignment. Then ream all of them? Perhaps by each hold sharing some misalignment, the oblong holes won’t matter as much?
 
they have offered to send me some new parts
I would have them send you two new sets. I would say odds are pretty good that you’ll be able to mix and match the new parts with your existing parts and have a good/much better fit. Also, clamp the two halves together before riveting and check free play in bearing. When I did mine it was fine while clecoed but was binding after riveting. In my case the primer in the recess caused the bearing to sit proud. Oh yeah, Don’t lose those bearings!
Cheers,
Todd
 
Thanks all,

Kevin is sending me a new set and I will see if I can get a pair which matches a bit better.

If not I’ll probably have to just accept them and move on.

Or buy a CNC Mill…. Hmmm
 
Can you assemble the bearing in the brackets, then use cleko side clamps to hold it together and have all the rivet holes share some misalignment instead of a few gross out of alignment. Then ream all of them? Perhaps by each hold sharing some misalignment, the oblong holes won’t matter as much?

This is an excellent idea. Thank you.
 
Just a data point. I’ve been following this because I was going to start working on these parts soon.

Well soon is today. Surprisingly, all the holes take rivets without effort.

This is strictly a comment about the parts and definitely not about my abilities which are weak to non-existent.
 
I sent an email to Vans a while back, recommending that they run off a batch of left and rights with only the bearing recess, no other holes. Install bearing, align edges, side clamp and match drill through original part with holes. Solve a lot of frustration for some builders.
 
Well soon is today. Surprisingly, all the holes take rivets without effort.
Is that with the bearings in place?

I sent an email to Vans a while back, recommending that they run off a batch of left and rights with only the bearing recess, no other holes. Install bearing, align edges, side clamp and match drill through original part with holes. Solve a lot of frustration for some builders.

I also suggested they do this but they elected to just send me some new parts. Hopefully they mass cut them and it’s only some out of each run that are affected (I.e. they cut 20 in a run but it’s just #6 set that is out etc)
 
I sent an email to Vans a while back, recommending that they run off a batch of left and rights with only the bearing recess, no other holes. Install bearing, align edges, side clamp and match drill through original part with holes. Solve a lot of frustration for some builders.

It's the bearing recess that was misaligned though. So while this would help with ensuring the rivets lined up, the edges would still not align.
 
So the bearing brackets sat in LA for 3 weeks then finally made a flight to aus - Van’s sent me a new L and R bracket pair.

I immediately tried the new ones alternately with their opposing part from the old misaligned pair. Same issues - the holes didn’t line up very well. Couldn’t get a rivet in.

I then placed the bearing in the 2 new brackets - the holes lined up nicely.

So, I surmise that when they machine the sheet with the recesses, they must do a whole bunch on the sheet at once. Perhaps, of the multiple recesses which get machined, one is out by a 64th in relation to where the holes get punched later? It seems that only some brackets coming out of the machine shop are misaligned.

Don’t know if Scott or anyone will see this feedback! But at least might be helpful to add to the wiki page 25-03?

Anyhow, the new brackets solved the issue and I’m glad I shelved these bits and got new ones. Haven’t riveted them together yet.
 

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Remember to clean primer out of bearing recess before riveting. Keep checking bearing free play as you rivet. Glad it worked out

Cheers!

I actually forgot to clean out the primer but I went very light on the bearing recess part. Used the squeezer and it worked out well. There’s some resistance in the bearings but no more that that they felt like before they went in.
 
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