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Dents and bolt holes

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  • Dents and bolt holes

    For the more experienced and technically minded members of the forum: I have some issues with a main spar. I am willing to rebuild my spar if necessary, but obviously not thrilled by the prospect. I have 2 issues that I need some guidance on:

    First is a bolt hole on a strut-attach bar. the bottom bolt hole on the strut attach bar (the one that goes through the capstrips) is elongated and requires upsizing. the hole is currently 0.296". An AN5 bolt is 0.305". Bob has suggested turning an AN5 down to the size of the hole. Given the difference of 0.009", can anyone say whether it is too risky to go up to an AN5 bolt instead of the intended AN4?

    Second issue is a dent on the spar. I will put some photos up by way of explanation. Any input on dent tolerances will be very much appreciated.

    IMG_2528.JPG IMG_2526.JPG IMG_2530.jpg IMG_2531.jpg IMG_2530.jpg
    Attached Files

  • #2
    Bradrock, In general, your dent is cosmetic, you can straighten or fill from what I see in the photos. I am sure the spar has a great deal of strength built into it to carry the given load. Given the edge clearance of the bolt hole you have described I would opt for the larger bolt. You can always increase. I think perhaps you must have misunderstood Bob. I would never attempt to decrease the diameter of AN bolt. You may set yourself up for a potential sheer point. Have fun! Stinger

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    • #3
      I agree with Stinger with one qualifier. In the top right pic, near the top right of the dent, it looks like there may be a slight crease. If so, I'd take a small fine round file to gently dress out any possible stress riser.

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      • #4
        This is heartening feedback. Thanks guys. Anybody else following, please weigh in if you disagree/agree.

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