What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Wing attach - hardware store bolts don't fit

wpisar

Member
QB 9A. Setting up for initial wing attachment. My problem is that the hardware store bolts do not fit through the F-904 plates. I know the bolts are fine as they easily pass through the wing spar. This is both the 1/4" and the 7/16" bolts. Has anyone else had this issue. What is best way to take a bit off the holes in the F-904s without damaging the holes in the center section.
 
On the 7/16 bolts, make sure you grind all the threads off and form the end to a polished bullet shape. Add a little wax or grease and they should "tap" right in with a soft block or block of wood and light hammer.

DO NOT DRILL OUT OR TAKE A LITTLE OFF THE HOLES!!!!!! These are factory fit and are perfect. dont mess with them, it will haunt you later!

If you are still having issues, check with the factory before you do anything. This is critical!
 
Last edited:
Are you sure that is where the interference is? The powder coating on the landing gear mounts made those holes slightly undersized and i had to remove a bit (of the powder coat only!) to install bolts...I would definitely NOT do anything to the f904 holes.

Chris
 
Roll the hardware store bolts on a perfectly flat surface, like a back-riveting plate, or granite tile. You may detect that the HW store bolts are not perfectly straight. I had the same issue. These HW store bolts are manufactured poorly from coiled rolls of material and they sometimes don't come out straight. Even the slightest curvature of the bolt will keep them from going through the bulkhead and spar holes. You may need to grind a bit off of the bolts, but don't mess with the precision holes on your airplane's spar or bulkheads.
 
Just finished the initial wing install on my -7. I used hardware bolts, 7/16 size only, didn't see the need to also go for the 1/4.

On the hardware store bolts I cut the threads off and rounded the tips to make a smooth bull nose as mentioned above. With some LPS they slipped in, but not without a lot of positioning by a person out on the wing tip moving the tips up down right left.

Do the Vans supplied close tolerance bolts fit thru the plates?
 
Last edited:
Van's response

Here is Vans response:

"This isn?t uncommon, and there?s no objection to gently taking a bit off the upright C and D components. Take great care not to damage the inside surface of the bolt holes. You can stick a wood dowl in the hole to protect it and use a dremel with light sanding drum to remove just enough of the upright to allow the bolt to pass through."

I requested a clarification and was told that I could expand the bolt holes in the 904s being careful not to damage the holes in the center section. I plan to check the bolts and try some lubrication but on some of those holes I can't even get the threads of the bolts in.
 
If you can't get the thread in the bolt holes, then remove the threads. You don't need them, since you aren't going to put a nut on the temporary bolts.
Grind off the threads, round out the end to a bullet nose shape and use some lubrication when inserting them. You don't need them super tight fitting. This is good enough for fitting the wings and getting the rear spar hole drilled. When you put on the wings for real with the close tolerance bolts, everything will line up again.
 
Some tips that worked for me.

Chuck the Hardware bolts in a drill press and polish the shaft to a smooth satin finish. Then cut the threads off and taper the nose of the bolt.

Lube the bolt and trial fit it into the mating holes on the wing and Fuselage and mark the holes and that bolt. By matching the holes and bolt before the wing is installed, you can obtain a smooth slip fit for each bolt without handling the wing.
I positioned the wings on sawhorses about a foot away from the fuselage to match pre-fit the bolts and mark the locations.

Then when installing the wing, the first bolt will slip in. The rest should slip in also. If the bolt is not slipping in, then you know the issue is wing alignment, not bolt fit.


I hope this is useful.
 
704 plates

It's too late but it may be the holes in the 704 plates on either side of the center section. When I was assembling the center section I noticed the permenant bolts wouldn't go through. I called Vans and was allowed to file just the plate holes. Fixed the problem.
 
Lathe

Had to turn the hardware store bolts on a lathe to make them round, then of course took the threads off. It is pretty crazy how out of round they were. I used grade 5 if I remember right. Wanted softer metal so it would not scratch the holes. Might have better tolerances with grade 8 bolts.
 
Back
Top