Can't get the drift pins in to mount the wings

We were to mount the wings of our 9A today but before we did we made drift pins from hardware store 6 inch 7/16ths bolts by cutting off the treads, and rounding the tips. Then we decided to try them in the center section before we mounted the wings. Much to our dismay, even after buffing off the finish on the bolts, lubing them and gently hammering them in we couldn't get them to go. I called Van's and they suggested removing the landing gear weldment which is no easy task, especially in reinstalling it. The bolts still wouldn't go, so we bought some more bolts in case the first were not straight; still no go. Another call to Van's was made and they suggested reaming the gusset on the outside fore and aft of the spar. This helped but it still takes some effort to get the bolts in and I am afraid that those bolts that are blocked by the weldment, will stick and we can't drift them out when we try to remove the wing.
If we are having this much trouble getting the lose tolerance bolts in, what will it be like to try to get the close tolerance bolts in. It is like the holes drilled in the center section don't line up just right.
HELP!!!!!

Measure

Cleve.... did you mike your "loose" bolts to see if they are truely a lesser diameter than the finish bolts?

gil in Tucson

All bolts are not equal

I help a friend with his -9 wing last month and of the 4 bolts that he bought as Ace two of them had to be milled down to fit in the spar/center section.

As Gil said, use a mic to see what size they really are.

Kent

Machine shop

I suggest getting a true measure on those bolts, get a dial indicator and see how many thousands your working with.. don't cut the spar , ream or anything else till you get the bolt sizes , the store bought bolts are several thousands less than the real bolts.. I am done with my drift bolts if you want them let me know..


Danny..

Cleve
I also had a problem with my hole alignment to the spar on my RV7A Q/B. The F-704C center section forward and the F-704 bar slightly out of align by just a few thousanths on just two holes. When I asked Van's about this they said others have had this problem. They suggested I use a Dremel tool with a small sanding drum, which is what I did, without touching the bar. I slipped a wood dowel from the back to protect the bar and removed the interferring part of the center section ( the part that goes up the side of the fuselage). Look up Brian Meyette's web site he had problems also. http://brian76.mystarband.net/RV-7Ahome.htm
Of course if this just interference of your landing gear weldments forget everything I just wrote. Good luck
Jim
Emp done, s/b wing done, q/b fuse close to done, working on 0-320 Lyc.

cleve_thompson said:

If we are having this much trouble getting the lose tolerance bolts in, what will it be like to try to get the close tolerance bolts in.

Click to expand...

Remember, loose tolerance doesn't necessarily equate to smaller diameter. It just means that the nominal diameter is less tightly controlled. The tolerance stackup could mean greater diameter than a close tolerance bolt.

-mike

I had a problem with my landing gear weldments on my 8A. The hole was the right size but the powder coat made the hole smaller. After removing the powder coat from the inside of the hole the bolts went right in. Simple solution but what a P.I.T.A. to do.

Center section drift pins now going in after trick with Dremel!

Jim,

I got a small drum sander for my Dremel and sanded the gussets after reading your idea. Now my drift pins will fit without problem. Now all I have to do is put my gear weldments back in and try to fit the wings! Thanks so much! What I really liked was the idea about the dowel to keep from going into the center section!

If for some reason you have the plane on it's gear with the engine installed, then you may have some slight deformity of the fuselage in the area of the spar carrythrough. The 100% full rigidity of the spar carrythough section is not complete without the spars bolted in place. The deformation may only be a thousandth or less but it could add to the issue. Try relieving the weight a little with an engine hoist if this is the case. It may facilitate the insertion of the bolts.

sacrifice

RV7AAAAAAA said:

Cleve
( the part that goes up the side of the fuselage). .

Click to expand...

not that it helps here but maybe others....this is why i sacrificed my 4 1/4" inch bolts to align those side pieces... otherwise there is some play ....they fit like a glove when i fitted the wings. 7a / also remove the powder coat ..sometimes it can be as thick as cake icing.

RV7AAAAAAA said:

Cleve
I also had a problem with my hole alignment to the spar on my RV7A Q/B. The F-704C center section forward and the F-704 bar slightly out of align by just a few thousanths on just two holes. When I asked Van's about this they said others have had this problem. They suggested I use a Dremel tool with a small sanding drum, which is what I did, without touching the bar. I slipped a wood dowel from the back to protect the bar and removed the interferring part of the center section ( the part that goes up the side of the fuselage). Look up Brian Meyette's web site he had problems also. http://brian76.mystarband.net/RV-7Ahome.htm
Of course if this just interference of your landing gear weldments forget everything I just wrote. Good luck
Jim
Emp done, s/b wing done, q/b fuse close to done, working on 0-320 Lyc.

Click to expand...

It took me awhile to find it myself, but here is a direct link to the page that describes what I had to do because I hadn't cleaned up the -A main gear weldment wing attach holes before mounting the gear.

http://www.meyette.us/FuselageNov06.htm

specifically, Nov 14, 15, 16, 17, 20 and link to May 6 http://www.meyette.us/fuselage.htm#may-06

HTH,
brian