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Bearings, Bushings or Steel on Steel

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  • Bearings, Bushings or Steel on Steel

    Making a ring roller with a capacity of 3/8 X 2 Flat with 3 1/2" rollers. Hand cranked through gearing. How much do bearings or bronze bushings reduce friction (torque) on a highly loaded, slow turning shaft?

  • #2
    http://www.roymech.co.uk/Useful_Tabl...o_of_frict.htm

    down the bottom there is a table of coefficient of friction for all sorts of materials...


    Precision takes time.

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    • #3
      Does it matter?

      The friction of various solid materials assumes "full contact" between them, i.e. no ball bearings, oil, etc. Metal-to-metal contact, in your case.

      Any bearing which is expected to last some real amount of time should NOT have metal-to-metal contact.

      Grease etc is intended to provide a film to prevent metal-to-metal contact. When that doesn't happen, it is called a lubrication failure, and the bearing is galled or worn into uselessness.



      [This message has been edited by J Tiers (edited 06-16-2005).]
      1601

      Keep eye on ball.
      Hashim Khan

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      • #4
        Bronze sleeves and grease cups aren't expensive or difficult to install and needle bearing inner rings pressed on the shafts make for a good surface that will last nearly forever.

        Avoid oilite bushings though,932 cast bronze sleeves are a few bucks more,but much more durable.

        Considering the load you will have(3-15tons depending on radius)handcranking may be very stressful.
        I just need one more tool,just one!

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        • #5
          Wow, I think the near 10+ tons needed to roll form 3/8x2 is going to be beyond bronze bearing capacity. Full complement needle bearings should do it though. Your shaft will need to be around 2 to 3" in diameter, depending on material used.

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