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SeatBelt attach point issue, help needed

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  • SeatBelt attach point issue, help needed

    Ok, no photos so I will do my best to describe the issue, I will post a photo tomorrow morning when I get to the hanger.

    The outside seatbelt attach point (think right for the right seat and left for the left seat) is extremely close to the fabric covering below the door frame. I am estimating the distance from the fabric to the seatbelt attach sleeve (goes through the seat support tube) to be 1/16 to 3/32”. Even if I had had the foresight to put the bolt in before covering it would still be in contact with the fabric.

    Possible solutions:
    1) Make a really nice covering job look like crap and poke a hole in it, install the AN4 bolt and patch over the hole. There would very likely be a protrusion even if the head of the bolt was shaved down a bit.

    2) Find an appropriate bolt (think metric possibly) that is just a bit larger than the AN4 and then thread the bolt sleeve so I could attach the seatbelt to the inside of the tube and not have any protrusion out the side. The seatbelt bolt is about shear, so this would in no way hinder the strength.

    3) Use an adel clamp and locate it below the bolt sleeve and subsequent welding which would stop any possible slide up the tubing in the case of extreme stress on the belt system. I have doubts if this would pass inspection, but I am just guessing. Note: I am attaching my retractable shoulder harnesses to the cross tube above and behind the seats using an adel clamp.

    I have spoken to Mark G and he liked the idea of threading the sleeve, he is going to check with the factory about the sleeve wall thickness.

    Obviously many of you have solved this problem previously, so I am looking for a good solution.

    Jay T
    N678C
    https://eaabuilderslog.org/?blprojec...=7pfctcIVW&add
    Revo Sunglasses Ambassador
    https://www.youtube.com/channel/UCQ0...tBJLdV8HB_jSIA

  • #2
    Put a helicoil into your list of ideas also. This was Bob's solution to a problem I had with rear seat attach bolts.

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    • #3
      jaredyates

      That Helicoil looks amazing. That will totally work. So, do you know what size I need to use for the sleeve that is AN4 diameter? Clearly there are some variables: 1) which diameter threader for the sleeve? 2) which helicoil for the now threaded sleeve?

      Edited to add: AN4 is a 1/4 - 28

      The sleeve is a bit of a loose fit for the AN4 when I slide it in. Would I order the 1/4 - 28 repair kit? Would the threading tool be oversized enough to work?
      Last edited by Utah-Jay; 10-31-2022, 08:37 PM.
      N678C
      https://eaabuilderslog.org/?blprojec...=7pfctcIVW&add
      Revo Sunglasses Ambassador
      https://www.youtube.com/channel/UCQ0...tBJLdV8HB_jSIA

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      • #4
        My recollection might be incorrect but I’m pretty sure the original design called for threading that bushing. I’m pretty sure that’s how I attached my belts.
        Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

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        • #5
          Whee is correct. I had the same thing happen and I have it in my kitlog, but kitlog is down. This is the EAA Log, but don’t know if you can see it. Bob is the one that recommended the Loctite solution since the bolt is in shear:

          https://eaabuilderslog.org/?blprojen...&listcat=&sid=

          Also, 1999 BearTracks talks about the seatbelt bushing.
          Last edited by alaskabearhawk; 11-01-2022, 01:32 AM.

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          • #6
            Ok, so it definitely gets threaded which makes perfect sense. It is a pretty loose fit for the AN4 as mentioned above, anyone remember what they upsized to? Jared’s idea of the Helicoil has a lot of merit
            N678C
            https://eaabuilderslog.org/?blprojec...=7pfctcIVW&add
            Revo Sunglasses Ambassador
            https://www.youtube.com/channel/UCQ0...tBJLdV8HB_jSIA

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            • #7
              In 303AP the bushing is threaded for a 5/16 bolt. The bolt is not an AN type, having a much shorter unthreaded section. There is a jam nut that tightens to the airframe which allows some pivot for the seatbelt tab. On 805TB I'm pretty sure I just tightened the bolt up and never missed having any movement for the tab.

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              • #8
                The helicoil worked great. I did not have the correct size handle for the the threader, so improvised as you can see below, but definitely the way to do it.

                Just do it before you cover
                F3B02190-0EE1-4A0D-88F7-2D2C662846BC.jpg
                CDB15E00-8946-41A5-B4BE-9EF0675BCB43.jpg
                N678C
                https://eaabuilderslog.org/?blprojec...=7pfctcIVW&add
                Revo Sunglasses Ambassador
                https://www.youtube.com/channel/UCQ0...tBJLdV8HB_jSIA

                Comment


                • #9
                  On mine, the bolt just goes through the fabric from the outside. It also holds a tab for ski cables.

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                  • #10
                    Originally posted by kestrel View Post
                    On mine, the bolt just goes through the fabric from the outside. It also holds a tab for ski cables.
                    Good info!

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