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Chain jumping off sprocket

Discussion in 'Chainsaw' started by jack76, Jul 4, 2011.

  1. jack76

    jack76 ArboristSite Lurker

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    I bought a husky288 and it came with a 20" bar. The bar had the same pitch and guage as the sprocket and my chain. When i went to cut the chain jumped the bar. I looked up the oregon number of the bar and found that the bar was for a eight toothed sprocket. The sprocket for the 288 was an 7 tooth. Could this have caused the chain to jump off? I have since bought the correct bar. I am milling with this saw on a logosol setup with a ripping chain and am new at it.
    Hard telling not knowing why the chain jumped, ruined my first chain. Maybe sprocket is worn so I will invest in another??
     
  2. lone wolf

    lone wolf Tree Freak

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    Now and then they come off but not often. if it happens a lot something is out off true or wrong .Notice what causes this if you can was it loose when it happened?
     
  3. jack76

    jack76 ArboristSite Lurker

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    jumping chain

    chain was tight. I was only cutting for 30 seconds.
    I will try my new setup tomorrow
     
  4. J.W Younger

    J.W Younger Tree Freak

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    I doubt the smaller diameter of the drive rim caused it, maybe othe issues with it.
    How about the fixture forcing the bar not straight?
     
  5. jack76

    jack76 ArboristSite Lurker

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    I will check on that tomorrow..Thanks
     
  6. lone wolf

    lone wolf Tree Freak

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    The more I think about it if the chain came off that fast for no obvious reason maybe it was not on the sprocket to begin with.
     
  7. jack76

    jack76 ArboristSite Lurker

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    Roger that
     
  8. jack76

    jack76 ArboristSite Lurker

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    reply to lone wolf

    Turned out the drum and sprocket were worn. I got another that was in better shape while I wait to buy a new one. I've been working on milling technique now. I also bought a new bar. The logosol timber jig takes some getting used to but each board comes out better.
     
  9. Philbert

    Philbert Addicted to ArboristSite

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    As others noted, the number of sprocket teeth should not have made a difference if the sprocket is for the correct chain pitch. If Oregon referenced that particular bar for use with an 8 tooth sprocket, it probably had to do with specifying the correct number of chain drive links to use with that combination.

    Philbert
     
  10. jack76

    jack76 ArboristSite Lurker

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    chain drive links to sprocket

    Thanks for the input...This site has great members
     

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