Michael Burbidge

Michael Burbidge

Well Known Member
I've finished my first fuel tank and I am now trying to mount it to the spar. Somehow the holes that I matched drilled in the spar do not fit perfectly. I'm having troubled getting bolts in some of the holes. They are just slightly misaligned. I matched drilled these per the instructions with a #12 drill bit. I'm wondering if it would be ok to enlarge some of the holes slightly with a #11 or #10?

Did you have problems getting the z bracket attach bolts into the platenuts on the spar? If so, how did you solve the problem?
 
try just barely starting all of the attach bolts first

things may move from your original match drilling if you tighten the bolts before getting them all started or if you begin to attach the tank to the leading edge join or spar before getting all of the z bracket bolts started. also you might try attaching from scratch and starting with the bolts that were most problematic first... just leave everything as loose as you can until you can get all of them started.
 
Use a cleco to get the bracket centered first...

I think a black cleco was the right one to use.

Something that seemed to help was starting a bolt into each and every nutplate, enough that a couple of threads had come out the other side, with the tank still on the bench. Did this also with all of the #8 screws.

After those steps, it seemed to work very well, and I was having trouble at first. I find out if the right tank will have this issue in about a week!
 
Similar issue..

I too had a problem getting some (but not all) of the bolts started. I think I was able to resolve it by oiling the bolts a little before trying to get them in again.

I agree that it would probably be easier to work out those issues on the bench. Make sure all the bolts will screw in, before mounting the tank back on the wing. I also used a centering type pick to get the holes lined up nicely before inserting the problem bolt.

I also agree that it is probably best to get all the bolts started before cinching any of them down tight.
 
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