Center Section / F-704

Brantel · Post by **Brantel** » Mon Aug 20, 2007 8:48 am

F-704 and center section riveting:

Is there any benefits to having the close tolerance bolts in the F-704 center section when drilling and riveting the entire center section together?

After completing the F-704 spar center section, I can see that the close tolerance bolts will be a pain to get to go in due to after riveting the side gussets on, they won't fit without some sanding of the side gusset opening. (I had the close tolerance bolts in when drilling the side gussets to the spar but did not have them in when riveting)

The instructions say to drill the spacer bolt holes out to accept a 1/4" bolt. I did this but when bolted all together, the front half does not perfectly align with the back half unless I loosen these spacer bolts slightly. My guess is that the 1/4" drill walked slightly in the pilot hole creating a slightly angled hole.

My fear is that I will rivet this all into the center section and then won't be able to get the bolts in due to this side to side misalignment of the two halves.

Will the bottom skin and all the prepunched holes guarantee alignment or should I sand the gussets, and insert the bolts temporarily until the center section is drilled and riveted?

cjensen · Post by **cjensen** » Mon Aug 20, 2007 9:04 am

Not a suggestion, just telling you what I did...

The pre-punchedness of the center section is so accurate, that I did not use the NAS bolts while riveting the 704 together. Everything came together just fine.

Now, the problem that you are experiencing is with this spacer?

If that's where you have alignment problems, and you have an angled hole, get a new one. You'll never get the bolt thru if the holes are not lined up.

I've reread your post several times, but without pics of the area/spacer in question, this is the best I could come up with...

Brantel · Post by **Brantel** » Mon Aug 20, 2007 9:16 am

Chad,

Thanks for the quick response...

I needed to explain it better. The F-704 is completely assembled and I had no problems with the area you are discussing (except that short rivet holding those shear bars in).

The above questions all revolve around these spacer bolts and the holes and drilling and riveting this into the cockpit floor/entire center section:

Hope this helps xplain it...

cjensen · Post by **cjensen** » Mon Aug 20, 2007 9:26 am

Ah! That makes it easier! Leave 'em out...it'll all line up. At least that's what I did...actually, I don't recall ever putting those bolts in at that point. Hmmm...

TomC · Post by **TomC** » Mon Aug 20, 2007 7:23 pm

I agree with Chad. Leave out the bolts. I did not install my close tolerance bolts until I put my wings on for good at the airport. They go in so tight, I will be in trouble if I ever have to take the wings off.

Good Luck,