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  • Annealing a file

    I'm trying to anneal a file so I can drill and tap couple holes in it and mount Biax scraping blades to use for hand scraping. This file was available and is the perfect size for my use. I've tried twice now to heat the last several inches cherry red with a oxy torch and then immediately shove it in a bucket of clean cat litter. I've only been able to get the holes halfway through from one side and it gets too tough to drill. I thought this method would work but apparently not and I'm guessing I need a longer heat and cool cycle. Fireplace season is over so I'm left with a charcoal grill option. If I soak it in the coals and just leave it to cool with the fire, do I have a chance of fully annealing the file? If not I'll just suck it up and find a piece of mild steel stock the right size, but it is an hour round trip to the supplier.

  • #2
    I thought the way to do it is heat it up to non-magnetic, keep it there for a few minutes, then let it slow cool.
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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    • #3
      Annealing

      I will look for my tempering charts but if the files are mostly 1095ish carbon steel and not an alloy or more complex steel, they need to be heated to a temperature past the Currie point or the temperature at which it no longer is magnetic.

      Since you are not doing a whole slew of these it might be just as easy to heat the file to a yellow heat, a little past the cherry red and then back the torch away and hold the temp there for 10 or 20 seconds and then begin top slowly draw the torch away and let the color drop slowly. If you have access to a plasma torch just burn the holes in as an alternative.

      Annealing is a time at temperature deal and it sounds like you need to spend a little more time hot to allow the heat to work its magic. If you have any ceramic wool, kaowool or even mineral wool you could place the hot metal in a blanket of that to let it cool slowly.

      Plain old carbon steel does not require lot to anneal it, but alloy steel can be much more difficult ie take temperature controlled furnaces and 12 to 24 hours to anneal.

      We forge air hardening steels like S7 and H13 as they work hot pretty easily, but in the home shop it is very difficult to anneal them. We work em' hot and then use them.

      paul
      paul
      ARS W9PCS

      Esto Vigilans

      Remember, just because you can doesn't mean you should...
      but you may have to

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      • #4
        Yea.. Don't dunk it into cat litter. Too cold, too much thermal mass.
        Just get it red hot untill a magnet stops sticking to it (I like I use a long bolt on the magnet to reduce the magnets strength, else you might end up bending the poor thing peeling it off the magnet red hot), then get it back to how hot it was before you tested it with the magnet and very slowly over the course of 60 seconds pull the torch back further and further untill the very tip of the flames are no longer touching the file (Should be red hot for at LEAST 20 of those seconds)
        If trying to not anneal the very tip, keep it covered in a wet rag.
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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        • #5
          I've had good luck heating them cherry red and just letting them cool down on their own.

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          • #6
            Stick it in bottom of a bonfire, and drink beer for 4 hours.
            In the morning, after the fire's cooled it will be annealed.

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            • #7
              This bad boy fought me all the way. I tried heating it cherry red, holding it for a there for a couple minutes and then slowly backing the torch away over a few minutes and then letting it cool at ambient. Got barely soft enough to get two holes through, but dulled a couple drill bits, had sparks and chip throwing theatrics, and ended up finishing them out with a carbide burr in the Dremel. No way I can tap so I'll use through holes and a threaded backing plate. Job's done, but what a pain. Next time we have a fire I'll throw a file in and see if that works better.

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              • #8
                You may need to heat the whole thing, then cool slow. There is a good chance that the unheated portion is drawing off the heat too quickly. Also, none of it needs to be hard since it is being used as a handle. You don't want it to shatter in your hands.

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                • #9
                  Originally posted by gzig5 View Post
                  I tried heating it cherry red, holding it for a there for a couple minutes and then slowly backing the torch away over a few minutes and then letting it cool at ambient.
                  It probably cooled too fast. Bury it in vermiculite or lime, and let it cool slowly.

                  Good, older files were W2. Good stuff!
                  "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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                  • #10
                    get a old used toaster oven,one with 2 heating elements, top and bottom, turn it on get both hot,and after heating file up to barely yellow, stick it in hot oven for a few hours.
                    Last edited by madokie; 04-28-2013, 09:05 PM.
                    FORD BEATING JAP CRAP SINCE 1941!! CAROLYN JONES(1930-1983 actress)may this lady never be forgotten.

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                    • #11
                      Is it possible that you are drilling at too fast a speed and hardening the surface that might be annealed?

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                      • #12
                        Originally posted by madokie View Post
                        get a old used toaster oven,one with 2 heating elements, top and bottom, turn it on get both hot,and after heating file up to barely yellow, stick it in oven for a few hours.
                        That won't anneal....

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                        • #13
                          I've never heard of using a file as a blade holder, we always used the flat metal braces that are used on power pole cross arms, they are tough try to get an old one the new ones don't seem to be as tough as the old ones

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                          • #14
                            Success!

                            The wife wanted steaks last night so I stuck the file in the middle of the pile of hardwood charcoal, and added a bit more than I would usually use. Once the oils burned off the file, I grilled the steaks and then piled all the remaining coals on top of it and let it burn down. This morning I drilled and tapped two 10-32 holes with no issues. The material is fully annealed. The file has an 1/8" bow in it, probably because the tang end was not in the hottest part of the coals. I'm sure it's going to warp a little even if it was uniformly heated. I'll put some heat shrink tubing around the body of the file to give a clean grip and call it a day.

                            As mentioned, I think the body of the file was sucking the heat too quickly out of the last two inches I was getting cherry red. I definitely learned a little bit on this "simple" project. Back to scraping.....

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