Gert Odendaal
Good day members

Please be so kind as to give me some info. 

Are all farrier rasps being manufactured equal?

What kind of  steel is a farrier`s rasp being made of?

What is the best method to make a knife from a rasp, forging it or stock removal method?


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jmccustomknives
Good question, not they most certainly are not.  Rasp are a crap shoot.  Many are case hardened steel meaning that it was made from a steel that has a low carbon content (wont harden) and is heated and carbon introduced creating an hard eggshell.  To test the rasp heat the tang (I do it with a torch) until a magnet quits being attracted then a little more heat and quench the tang in water.  After it cools put it tang up in a vice and strike the tang with a hammer (safety gear!).  The goal is to bend or break it .  If the tang breaks like glass it should be good, bending means it didn't harden.  You can repeat the test if you'd like, I throw the file in the scrap pile if it fails.

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Hank Rearden
Here's a link to test on files. http://www.theironforgefire.com/post/bushcraft-fire-steel-using-coal-forge-flat-file-and-12-round-stock-7349621?pid=1288421723
code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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Anthony San Miguel
I wouldn't bother trying to make a knife from Bellota brand rasps. Supposedly they are good for what they are meant to be, farrier's rasps, but are very often case hardened so won't make a good knife.
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jmccustomknives
I agree, the Bellota's aren't worth looking at for knives.  Really, the only farriers rasp I've ever found that tested out very well was a large (18") Heller.  Which is ironic because I don't like their files at all.

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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omegaman66
Sorry to revive this old thread but I have a question.  If the metal was only case hardened why toss it.  Couldn't you just add more carbon yourself?  Or is this just to much work to worry with even if it is possible.
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jmccustomknives
omegaman66 wrote:
Sorry to revive this old thread but I have a question.  If the metal was only case hardened why toss it.  Couldn't you just add more carbon yourself?  Or is this just to much work to worry with even if it is possible.


Good question.  When the steel reaches the austinitic state the carbon atoms move in the iron much like water does in a sponge.  Like water moving from the wettest portion to the dry carbon moves from the area with the most carbon to the least.  Now here's the rub, this movement is equivalent to about the width of a human hair an hour. 

So you have guys claim to use a carborizing flame, or in some manner "add" carbon to their billets.  All that black stuff that flakes off the steel as it is worked is scale, or burnt steel.  Carbon is one of the first atoms that oxygen wants to combine with so what happens is as the steel is worked any carbon put in during the heat is lost to scaling.  This carbon loss is why forge theory says to leave a grind tolerance.

It is true in the past that case hardened knives were made, usually trade items, but they were inferior to homogeneous steel blades.  The natives that used those blade had to sharpen from one side only because to sharpen like a normal knife would leave the edge in the soft steel.

Rule #10;  "I can make that" translates to; "I'm to cheap to buy it new."

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Hank Rearden
I keep learning new things. Thanks for the questions and answers folks.
code[Maglio.gif]  Keep the fires burning hot!
2020 ABANA Conference in Sarasota New York. June 3rd. through June 6th. Plan now!
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omegaman66
Awesome thanks.  Wow I am so new to this, I know next to nothing.  Great info!  This helped me alot!
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omegaman66
I have added a link to this website.  You can see it at near the bottom of this page: http://www.survival-manual.com/blacksmithing/blacksmithing.php
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