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Tight Fitting Annulus

  1. Sep 29, 2009 #1
    I have a problem at work!

    We have a large annulus that we need to fit a shaft into. I have calculated the tonnage required and it is outside of our workshop facilities.

    Any ideas, Lub, etc?
  2. jcsd
  3. Sep 29, 2009 #2

    Ranger Mike

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    i would not comment on this post if i had too!
  4. Sep 29, 2009 #3
    Its a real tricky problem in my line of work. I am worried about damaging the shaft.
  5. Sep 29, 2009 #4
    could the shaft be cooled with LN2 and the outer piece be heated? If you know what the interference fit of the 2 would be, simple expansion contraction formula would tell if its doable

  6. Sep 29, 2009 #5


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    Heat the outer and chill the inner. That is about all you can do. Like was mentioned, use the materials to find out the CTE of each component and find out the delta T required to give you the clearance required for assembly.
  7. Sep 29, 2009 #6
    i guess this is one of those questions you have to be really careful in how you word it.:smile:
  8. Sep 29, 2009 #7


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    Some of the equipment on the paper-machine had interference-fit sleeves on shafts, and the millwrights fit them by putting the sleeve/collar/etc in a large portable induction heater until it had swelled sufficiently, then quickly pressing it on the shaft. I don't recall them ever cooling the shafts, but the sleeves were plenty hot when they went on.
  9. Sep 30, 2009 #8
    Thanks for all the help with this one guys. Yes I see your point with the wording, there are alot of terms in engineering that can be considered something else if you have a dirty mind. Anyway, I heated the annulus and slowly tried to press the shaft in, however the shaft has buckled on insertion. :(
  10. Sep 30, 2009 #9
    too much interference at ambient conditions
    too big a hammer
    sorry it didn't work

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