Well, after reading this recently revived old thread:
https://vansairforce.net/community/showthread.php?t=47846, I am once again concerned/unsure about the filing of the stub spars.
Specifically this exchange [Text in brackets are mine]:
In this case, the manual does not say to file on the stub spars if/as needed. [When attaching/fitting the completed wing for the first time]
The only time the manual says to do any filing on these parts is during [fuselage] construction. Even then, it says to do only enough to get a close fit between the parts so that they fully mate together.
Scott, Beg to differ a bit. The general instructions, tell you to remove the machining marks/nubs from the parts to eliminate any stresses. In this case, that is all I did. Yet still needed a small shim.
Maybe in this case, a special instruction in the plans is needed to ensure the builder removes ZERO material from these areas. When I fitted the parts per the plans, they fit just fine. Now I realize, a loose fit here would NOT be detected.
The step says: "File the rear stub spar rounded ends of both wings to
closely fit the recessed machined curve of the F-1206C."
I didn't file away extra material all will-nilly, but I was focused on getting the best "closely-fit" I could get, because there was no other guidance given.
The instructions do not stress the importance of removing only the absolute bare minimum necessary.
It's been a while since I did this step, so I can't really say how much I removed, but based on Marty's experience it sounds like any filing here could be too much?
Something else in that thread prompted me to go look at the maintenance manual, which has this to say about the Condition Inspection: "If the W-1207B rear spar doubler has been trimmed too much, the finished airplane may exhibit some play at the rear spar junction. This is usually discovered by hearing a “click” and detecting in/out movement when the wing is installed. Increasing the length of the spar doubler is not possible, so it must be removed and replaced with a different, slightly longer, part."
If this fit is indeed so delicate, then I agree with Marty, it should have been stressed in the KAI.
The other thing here is that there is no mention of using a shim, just says must remove and replace?
I haven't built the wings yet, so I guess I'll just order another set of rear spar stub-doublers, either to just compare my filed parts to, or maybe just toss the old and use the new, being extremely careful during deburring. Thoughts?
And lastly, what about the forward stub, where you are supposed to file the recessed socket to "closely fit" the stub? Is that connection just as finicky?
...Or am I massively overthinking this and should just finish the *&^%! build and then shim if needed?