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  • Bushing, spacer material

    Any opinions on what material makes for better bushings/spacers? There are a few in the controls. SS will gall, and rust a little. 4130 rusts more. I need to make a dozen or so.

  • #2
    I responded a little while ago but it didn't go through. John - where specifically do these bushing/spacers go? Mark

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    • #3
      On one end of most control cables (not all) I have a MS-21259-4rh swaged threaded stud. The only AN fitting is an AN665 threaded fork but the hole diameter is .25". I looked through sailboat hardware and 1/8" cable ends all had .25 pin holes. The only thing I found with the right hole is the MS27975 threaded fork. It is normally used for engine controls. I bought one and it looks more than strong enough, but I already bought all of the AN665's, and they aren't cheap. But I need bushings to go from 1/4 to 3/16. I already made them in 4130, I am just wondering if that is better or worse than stainless as a bushing material.

      I am hoping to get away without any turnbuckles. Maybe one for the ailerons cable loop. I am putting the wings back on in a couple of days to verify all the cables function, and get the fuel connections sorted. Then pull the wings and close them.

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      • #4
        Decades ago I used to get small parts cadmium plated. I think that if possible having your steel bushings plated would be a good option. Cadmium would help prevent corrosion but also provide some lubrication.

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        • #5
          John - you should have gotten with your kit a 1 ft piece of 4130 tubing in 1/4" x .028. This is sent for you to make bushings where needed. You can paint them or just grease them. Should last a long time. The idea(in certain places) is to have this tubing be a little bigger than just filling the hole (as a bushing) and have it actually what tightens up against the nut/bolt.

          Using the swagged ends is good if you are able to get the cable lengths just right as there is little adjustment with the threads on that stud end. I have mostly given up after trying that a few times and rarely getting the lengths correct. But others (probably you) can get the lengths more accurate. Mark

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          • #6
            Mark, so in this application, you also think the bushings should be proud of the clevis fork, and the bolt should tighten up to the bushing?

            The combination of the AN665 and the swaged stud have almost an inch of adjustment range, almost double that of an AN turnubuckle. The straight runs are easy to get the length correct. The forward aileron cable is a bit tougher as it goes through 3 pulleys. For that reason, and a couple of others, the control stick end of the aileron cable I left as the tag end, and I will put a nicopress end on it. The control stick to pulley, and the flap arm also are a bit awkward with the way they guide the cable into the pulley, so I thought a nicopress type fitting would be a bit more appropriate.

            So far so good. I will see how it all feels when I hook it up this week.

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