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Homemade File Knife

Discussion in 'Do-It-Yourself & Gear Modifications' started by JUNK, Feb 20, 2012.

  1. comando293

    comando293 Loaded Pockets

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    Normalizing is heating the steel until all of the atoms are aligned. This is the first step of annealing. Then it is cooled slowly, so that the steel remains soft(er). The piece is then worked, producing new internal stresses. Normalizing again removes the stresses.
    Tempering (with oil) introduces a differential in hardness.

    Basically, cool the steel slowly to make it soft, and quickly to make it hard. Too hard and it cracks/chips, too soft and it deforms instead of bending. The process ZippoVarga described will work just fine for a generic tool steel like these old files. If you knew the exact composition of the steel, you could look up the specific temperatures and times to produce the properties you wanted, but who cares if its not perfect? Just make another one.
     
  2. Lightnig

    Lightnig Loaded Pockets

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    No, quite different

    In a nutshell, to bring to terms to the simplest form:

    Hardening is done to alloy steels to make the hard. However the raw hardness of the initial heat treatment will leave a steel alloy extremely brittle

    Tempering is done to draw out the excess hardness of a heat treated item so that it can be useful without breaking. The intent of tempering is to increase desirable mechanical properties such as ductility, elaticity, and impact resistance while still retaining enough hardness to not easily deform.

    Annealing will bring the material to it's softest possible state. This will facilitate working the material

    Normalizing is typically done to refine the size of carbides (rule of thumb: small carbides good, large carbides bad) and other crystalizations at the atomic level. It will also bring the steel grain patterns to consistent state (this is where the term normalizing is derived from). Normalizing will also relieve any internal stresses that may exist. This last is far more important in a welded or joined object, rather than one machined out of a single piece of material. - For purposes of knifemaking, you can safely ignore Normalizing unless you start getting into forging or other high end operations.



    The give an example of hardening, annealing and tempering:

    Wayyyy back in my college days, I spent a fair amount of time in the blacksmith shop (it was a regional Ag college). The shop have an ample supply of O-1 tool steel that I had pretty free access to. so I grabbed a handful of 5/8" round O-1 rod and too it over to the welding shop.

    in it's raw from from the mill, it could be worked with a file, bent with a hammer and vice, and drilled with a hand drill. It was still very hard, harder than standard mild steel but it was still workable.

    I then took one bar, took an acetylene torch with a rose bud and heated a bar to the verge of melting, I mean HOT - far beyond what would even be done during a heat treat. When I was sure it was good and hot right to the core, I threw it in a water tub and rapidly agitated. This cooled it far more rapidly than it should have been, being an Oil hardening steel (which cools slower than water).

    The result was 5/8" bar of steel that was EXTREMELY hard. It could not be filed, drilled, or worked in any way. I have no adjectives to describe how hard this steel was. However, it was extremely brittle. I accidently dropped on a steel workbench from a height of about a foot and a half, and it snapped in half. I smacked one piece with a hammer, and the tool steel literally shattered. The stuff was literally like glass.

    I then took a third piece and annealled it. Chucked it into a HT oven to bring it up to temp (sorry, don't remember the temp), along with a steel bin full of sand. After had sat in the oven for the right amount of time, I put the bar into the sand and put the let it cool down over the weekend.

    The result was an annealed bar that had no hardness what so ever. It was softer than mild steel even. so easy to file and shape, could bend it like a noodle with a short snipe. ended up putting it into Pretzel shape, just for the heck of it.


    And no, I didn't just waste the material on stupid tests. I ended up hand forging a few into knife blanks and flat bars for making other stuff.
     
  3. Lightnig

    Lightnig Loaded Pockets

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    Oh, and wanted to say the following:

    I like the looks of the knife you made, very cool. Good job. [​IMG]


    However, it is likely too hard to be useful. In order to be able to work on other steels, a file must be considerably harder than normal metals. (remember my example of the too hard tool steel above).

    I suspect that your knife is very brittle, and the edges will easily chip, or even break out in chunks. any attempt to pry with it will most likely snap the blade.



    Not to try to dissuade you at all, I applaud your effort. But to put a bunch of work into a blade, do what you can to make the knife one you can use and enjoy.

    Do another one, but this time get it heat treated (before you put a handle on it). I am sure with a little research you can find a local maker with their own oven who will HT your blade for you for a small nominal cost, maybe ~ $20?
     
  4. JUNK

    JUNK Loaded Pockets

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    Thanks for the great input. This OS what I suspected. I will try to treat the metal with the recommendations above but I'm sure this will take some practice. Do you guys know of anything to recycle into a knife blade that will already be appropriately hardened?

    Sent from my LS670 using Tapatalk
     
  5. Megavolt

    Megavolt Empty Pockets

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    Do not reinvent the wheel. At home, a good knife is not done, heat treatment is poor.

    Read here http://en.wikipedia.org/wiki/Damascus_steel.

    Buy a blade, and fabricate a nice grip to it.

    Here's an example (not advertising) http://damask.ruprom.net/product_list/group_687771. This site has an English translation.

    Or this



    For my knives, I use steel from the valve diesel engine locomotive. The complex chemical composition, alloy steel. I do them at the factory, where have all the necessary equipment. It is a guarantee of high quality. Where there's a will, there's a way. Good luck!