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Re: [atlas_craftsman] Suggestions for heat treating a threaded plate?

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  • Rexarino
    Welders use milk of magnesia to protect critical parts, don t know if it would help during hardening. Anything that keeps oxygen away from the surface will
    Message 1 of 12 , May 31 10:07 PM
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      Welders use milk of magnesia to protect critical parts, don't know if it
      would help during hardening. Anything that keeps oxygen away from the
      surface will help. Not sure how you would dunk in oil/water, but heating
      in a stainless steel bag with some carbon (coal, etc to burn oxygen out of
      the trapped air) then maybe remove from the bag and chill it.

      Rex

      On Thu, May 31, 2012 at 12:02 PM, Not <sstephanc@...> wrote:

      > Hi all,
      > I am making a specialized gear puller from 5/16" thick truck leaf spring.
      > I would like to heat treat it once I am done machining it. It has several
      > threaded holes, so I would like to treat it in such a way that the threads
      > are not damaged by the formation of scale from the heat treatment. So far,
      > my available heat sources are a wood or charcoal-fired forge or a
      > similarly-fueled foundry. Any suggestions? I might try the tool first to
      > see if heat treatment is necessary.
      >
      > Thanks,
      >
      > Scott
      >
      >
      >
      > ------------------------------------
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      [Non-text portions of this message have been removed]
    • Bruce .
      I suspect you re overthinking this. Try an experiment: Take a black iron (i.e., steel w/o any plating) nut with threads roughly the same size as you ve
      Message 2 of 12 , Jun 1, 2012
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        I suspect you're overthinking this.

        Try an experiment: Take a "black iron" (i.e., steel w/o any plating) nut
        with threads roughly the same size as you've tapped. Heat treat it exactly
        as you plan to do your workpiece.

        Now before you do anything else, try this nut on a bolt of the appropriate
        size. If it doesn't fit, run a wire "bottle brush" through it -- rotating
        the brush -- and try again. If still not satisfied, put it in white
        vinegar overnight, then try it again.

        It's true you get oxidation, but it may not be as much as you think.

        On Fri, Jun 1, 2012 at 1:07 AM, Rexarino <rexarino@...> wrote:

        > **
        >
        >
        > Welders use milk of magnesia to protect critical parts, don't know if it
        > would help during hardening. Anything that keeps oxygen away from the
        > surface will help. Not sure how you would dunk in oil/water, but heating
        > in a stainless steel bag with some carbon (coal, etc to burn oxygen out of
        > the trapped air) then maybe remove from the bag and chill it.
        >
        > Rex
        >
        >
        > On Thu, May 31, 2012 at 12:02 PM, Not <sstephanc@...> wrote:
        >
        > > Hi all,
        > > I am making a specialized gear puller from 5/16" thick truck leaf spring.
        > > I would like to heat treat it once I am done machining it. It has several
        > > threaded holes, so I would like to treat it in such a way that the
        > threads
        > > are not damaged by the formation of scale from the heat treatment. So
        > far,
        > > my available heat sources are a wood or charcoal-fired forge or a
        > > similarly-fueled foundry. Any suggestions? I might try the tool first to
        > > see if heat treatment is necessary.
        > >
        > > Thanks,
        > >
        > > Scott
        > >
        > >
        > >
        > > ------------------------------------
        >
        > >
        > > TO UNSUBSCRIBE FROM THE LIST:
        > > You do this yourself by sending a message to:
        > > atlas_craftsman-unsubscribe@yahoogroups.com
        > >
        > > Atlas-Craftsman Projects list is at
        > > http://groups.yahoo.com/group/atlas_craftsman_projects/
        > >
        > > To see or edit your personal settings, view the photos, files or links
        > > http://groups.yahoo.com/group/atlas_craftsman/
        > >
        > > The Atlas-Craftsman Wiki is at
        > > http://pico-systems.com/cgi-bin/Atlas-wiki/Atlas.cgi
        > > Please submit things you think will be useful to Jon Elson at mailto:
        > > //elson@...! Groups Links
        >
        > >
        > >
        > >
        > >
        >
        > [Non-text portions of this message have been removed]
        >
        >
        >



        --
        Bruce
        NJ


        [Non-text portions of this message have been removed]
      • James Irwin
        Ashes are a great idea. Carbon provides a reducing atmosphere. Tempering is a function of temperature and time. Is your measure a thin-crust or thick crust
        Message 3 of 12 , Jun 1, 2012
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          Ashes are a great idea. Carbon provides a reducing atmosphere.
          Tempering is a function of temperature and time.
          Is your measure a thin-crust or thick crust pizza? (Hah!)
          Borax will also provide a fluxing (reducing) environment. When the molten
          borax cools, it will solidify and stick the parts together, perhaps somewhat
          tenaciously. Should break free if clearance is sufficient.

          Jim I


          On 5/31/12 9:31 PM, "Not" wrote:
          >
          > I heat it & beat it to get the curve out of it. Then I got it bright red hot,
          > and buried it in a bucket of ashes to cool. That annealed it well enough for
          > drilling & tapping, which was already done before my initial post. I think
          > ashes work better than sand. I find tempering to color a bit too difficult to
          > judge and to get even. I prefer to put it in a 500 F oven for an hour. Lets me
          > cook a pizza at the same time. The real problem was how to avoid damage to the
          > threads. Putting bolts in the holes may work well, as would a reducing flame
          > in the forge. Borax and bolts may result in stuck bolts. Maybe bolts &
          > graphite.
          >



          [Non-text portions of this message have been removed]
        • Deloid
          ... Scott... as Jim stated above. He has the sequence and terminology down pat. I would add that since this is an unknown steel 9might be 5160)I would stop at
          Message 4 of 12 , Jun 1, 2012
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            --- In atlas_craftsman@yahoogroups.com, James Irwin <jirwin1@...> wrote:
            >
            > You¹ll need to anneal it first. Heat to dull red and let it stay that hot
            > for a while. Then cool very slowly, probably in dry, fine sand. Playground
            > sand. That¹ll make it sot enough to drill and tap. And will make it bend out
            > of shape under stress. So you¹ll have to harden and temper it after you¹re
            > done forming, drilling and tapping it.
            > Heat to cherry red, then quench in old motor oil. Polish a surface so you
            > can watch tempering, your next task.
            > Heat it gently and uniformly until the polished steel starts to turn blue.
            > Now set it aside to air cool. That oughtta do it. Should be a spring again.
            > The red heat will develop some scale in the tapped holes, so you may have to
            > clean the threads with a tap after tempering is done.
            > T¹ain¹t hard
            > Good luck.
            >
            > Jim I
            >
            >
            > On 5/31/12 2:02 PM, "Not" wrote:
            > >
            > > Hi all,
            > > I am making a specialized gear puller from 5/16" thick truck leaf spring. I
            > > would like to heat treat it once I am done machining it. It has several
            > > threaded holes, so I would like to treat it in such a way that the threads are
            > > not damaged by the formation of scale from the heat treatment. So far, my
            > > available heat sources are a wood or charcoal-fired forge or a
            > > similarly-fueled foundry. Any suggestions? I might try the tool first to see
            > > if heat treatment is necessary.
            > >
            > > Thanks,
            > >
            > > Scott

            Scott... as Jim stated above. He has the sequence and terminology down pat. I would add that since this is an unknown steel 9might be 5160)I would stop at the quench and check to make sure that a file slides like it is glass after the quench (compare to annealed piece)then rush it to the oven for the temper. An oven at 400 degrees for 1/2 hour is a start or you can gently use a torch to bring it to blue. Incidentally, regarding the tapped threads...protect with anti-scale from Brownells. Another way to prevent scale is to get to the quenching heat in a forced air environment (mentioned) or to burn wood with the metal. Burning the wood though blocks your color evaluation so you would have to go by a thermocouple.
            Another method- Pre-bore the hole then tap with a high quality tap...it will work in the (what should be) rockwell hardness 57 region.
            Good luck,
            Dean
          • Not
            I m done with the hardening, but it s too hot here in Chicago to do the pizza oven tempering. I threaded in screws with a light coat of anti-seize lube. The
            Message 5 of 12 , Jun 28, 2012
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              I'm done with the hardening, but it's too hot here in Chicago to do the pizza oven tempering. I threaded in screws with a light coat of anti-seize lube. The fire was probably reducing enough to make these precautions unnecessary. Once quenched, the screws backed out by hand and the threads look fine.

              I clamped a 1/4" ball bearing between a piece of the original annealed stock & the hardened piece. I got a 2mm dent in the annealed stock, but only a shiny flat spot on the work piece proving that it is much harder than the same material as annealed.
            • Doc
              not sure what you are doing or what material used , but a kitchen oven has served me well for years .... 0-1 ...375 -400 leav in oven for one
              Message 6 of 12 , Jun 29, 2012
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                not sure what you are doing or what material used , but a kitchen oven has served me well for years .... 0-1 ...375 -400 leav in oven for one ohour & turrn oven off to cool ( for metal cutters , c/bores reamers ...i can draw all the way down to a purple ...spring steel blue takes abt 560
                best wishes
                doc



                -----Original Message-----
                From: Not <sstephanc@...>
                To: atlas_craftsman <atlas_craftsman@yahoogroups.com>
                Sent: Fri, Jun 29, 2012 12:30 am
                Subject: [atlas_craftsman] Re: Suggestions for heat treating a threaded plate?




                I'm done with the hardening, but it's too hot here in Chicago to do the pizza oven tempering. I threaded in screws with a light coat of anti-seize lube. The fire was probably reducing enough to make these precautions unnecessary. Once quenched, the screws backed out by hand and the threads look fine.

                I clamped a 1/4" ball bearing between a piece of the original annealed stock & the hardened piece. I got a 2mm dent in the annealed stock, but only a shiny flat spot on the work piece proving that it is much harder than the same material as annealed.







                [Non-text portions of this message have been removed]
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