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Does Durabar have grain?

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  • Does Durabar have grain?

    I picked up a chunk of Durabar to make beveled straight edge with. When I started roughing it in, I noticed it had a "grain" to it. You can see from the pictures that it's not just a surface blemish. I'm not really worried about it, I was just wondering. I thought the point of Durabar was that it had extremely uniform structure?


  • #2
    If you are refering to the lines in the left picture, going at right angles to the bar, they are freeze lines from extrusion.
    The bar is not moving at a constant speed and is extruded at 2 or 4 inch length with each stroke of the form die. They are continuously cast, but that is a kind of reciprocating motion.There would be a grain going with the bar as the molecules line up during extrusion.
    As the metal freezes, the rod moves to allow more molten iron into the form.

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    • #3
      Thanks, I assumed it was something like that

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      • #4
        I've been using durabar/versabar for years, and have never seen anything like that.

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        • #5
          I've milled a lot of DuraBar and VersaBar, and I've never seen anything like that first picture either.

          Both have superb tech support -- you might call them and ask: 800-227-6455

          http://www.dura-bar.com/
          "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

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          • #6
            From past experience . I would say that is a bad piece of Dura Bar Metal cooled to fast while being extruded. I have seen as such and some times it will crack in those spots , are brake under stress .
            Every Mans Work Is A Portrait of Him Self
            http://sites.google.com/site/machinistsite/TWO-BUDDIES
            http://s178.photobucket.com/user/lan...?sort=3&page=1

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            • #7
              Hmmm... interesting. I don't think it will see much stress being used as a straight edge (hopefully it remains straight), but maybe I'll give them a call, out of curiosity sake. BTW Lane, I recently sold a Van Norman dividing head on ebay and referenced your site to show that the gearing could be made. Hope you don't mind

              Tom

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              • #8
                When Molten Iron is cooled too quickly, it forms whats called White Iron, or chilled Iron.
                White Iron is very hard and difficult to machine.
                Trying to machine "window weights" is a good example .
                Now the waves or lines you see are not white iron, but are symtomatic of the temperature change and more than likely slightly harder than the rest of the bar.
                when the cutter hits the harder iron, the cut changes characteristics and a shiny surface is revealed.
                You can always get a much better finish on hard steel than on soft steel, and this is a living example of it.

                Rich

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