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delrin...what durometer??

Discussion in 'The Hokey Ass Message Board' started by Dan, Feb 27, 2013.

  1. Dan
    Joined: Mar 13, 2001
    Posts: 2,370


    Thinking of making some leaf spring bushings out of delrin, what delrin will be the "correct" durometer (isn't that how hard it is???) thanks-
  2. Weedburner
    Joined: Nov 16, 2010
    Posts: 207

    from Wa State

    I prefer the black stuff, it machines much better. Never had them ask what duro when i order it from Professional Plastics.
  3. Honestly I don't think you want to do that. Leaf spring bushings should have some compliance so that they can assist with the twisting of the spring during articulation.
    Delrin is very hard stuff generally around 120 Rockwell (it is too hard of a surface to get a Durometer rating), where as the rubber used in spring bushings is about 1/2 that!
  4. tudorkeith
    Joined: May 10, 2009
    Posts: 454


    Can you find a set of poly-urethane bushings already made?

  5. Maybe I have had just dumb luck, but I have made a few sets out of delrin with no issue both front buggy and real leaf. Got my delrin from McMaster Carr

    Wear- and Water-Resistant Delrin® Acetal Resin

    Considered the workhorse of plastics, Delrin® acetal resin combines moisture resistance and a slippery, wear-resistant surface with an ability to hold tight tolerances. Often used for gears, bushings, impellers, and other parts that require its strength and rigidity.

    Rigid Glass-Filled Delrin® Acetal Resin

    Composed of 20% glass for increased rigidity, this material is wear and water resistant as well as an excellent electrical insulator.

    Ultra-Wear-Resistant PTFE-Filled Delrin® Acetal Resin

    The addition of PTFE provides this water-resistant material with a more slippery, wear-resistant surface.

    General-Purpose Plastics Selector Pack

    This pack contains samples of 15 general-purpose plastics.
  6. JEM
    Joined: Feb 6, 2007
    Posts: 1,040


    Lots of leafsprings suspensions have used hard - bronze, Delrin, - bushings, or even just unbushed (way back when), with the bolt riding directly in a honed spring eye. Was just reading a 1914 issue of Horseless Age on this topic, as a matter of fact...gotta love Google Books.

    But it does mean that as body roll twists the spring, that twist will not be handled by the bushing, the spring itself has to twist. So your effective spring rate over one-wheel bumps goes up slightly. Think of it as a very small sway bar.

    And yeah, Delrin is hard enough that any difference in hardness between specific grades of the product isn't going to matter for this purpose. I'll note that you might find the bolt hole eggs out around the bolt because of the point load on the Delrin, if you want to go down this road check out Global West's Del-A-Lum bushings as a design guideline for an approach that spreads out the load on the Delrin better.
    Last edited: Feb 27, 2013
  7. mattrod68
    Joined: Jan 22, 2007
    Posts: 524


    the ptfe infused stuff i get from grainger is awesome for bushing type jobs its a brown color and has a non stick, self lubricated feeling.


  8. looks like a nice bushing, alum and delrin combo for a rear leaf spring and A-arm's what about smaller OD / ID apps like on a front buggy?
  9. if you want something with a little give use some
    bt delrine is fine
  10. Check these guys out for ready-made Delrin bushings.. They market them under their brand name of Del-Alum...

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