Yaw bearing

Discussion in 'Frame Construction' started by timber, Dec 19, 2010.

  1. timber

    timber WindyNation Engineer

    I have a 2-1/2" pipe tower with a piece of 5/8" diameter steel rod sticking out the top.
    A piece of 1/2" Sch40 pipe fits over the rod but doesn't turn easily so I want to use the half inch pipe as my inner bearing race.

    Anyone know what size (steel) pipe fits nicely over a piece of 1/2" Sch40 pipe?
    The O.D. of the 1/2" Sch40 pipe looks to be 7/8" diameter ...
    Would a piece of 1" Sch40 pipe work over that (8" length) or do you think it would be too sloppy a fit?

    Another way I can do this is to hone out the 1/2" Sch40 pipe slightly to fit over the steel rod ... if the 1" Sch40 pipe doesn't work.

    Any suggestions?


  2. TomT

    TomT WindyNation Engineer

    Biggest question is what are you going to put on this yaw bearing may I ask. I hope it is a mini test turbine or wind vane. 1 inch steel pipe is just over 1 inch ID and would be sloppy. If you could find 1/2 inch OD rod or all thread it would be a better fit as I do not know how long it would take to hone it out.
  3. timber

    timber WindyNation Engineer

    Hey Tom,

    Ya, I found a chart showing Sch40 I.D.s and O.D.s and they're not a good match at these smaller pipe sizes.
    I think my best bet is to use the half inch pipe directly on the steel rod. I can push the pipe about a half inch onto the rod now and by just using some sand paper around a drill bit in the drill press I can get the pipe to fit over the rod with a nice close fit that will turn freely. I'll also use some emery cloth on the rod so together it should do the trick.
    Grease that up good and it should be good to go.

    I had pillow block bearings on the rod previously and it worked ok but was just too free turning and did too much seeking with slight wind direction changes. I'm putting a Windynation 500 PMA on this but I don't think the rod will bend, my last turbine had 5 ft diameter blades and the rod held up with no signs of bending.

    I'll let you know how it turns out.


  4. TomT

    TomT WindyNation Engineer

    Seeking is why I put that post up about the scissor tail also as Bluejay posted a bigger tail will help stop it too. I will try it out later but I was going to have it just at the end with a 30 degree angle and the tips angled 15 degrees more. 2 ft tall and 1 foot wide. I have alot of turbulence here so it should be good test. Going to try the spring loading on 1 side to see if it will furl before I modify mine.
  5. timber

    timber WindyNation Engineer

    I'm going to go with a larger and slightly longer tail than before also. Should smooth things out, I think.

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