Hayden H

It BROKE!!!!! Forged/ground Nicholson file knife

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I have put in around 8 hours of time into the blade, forged it to shape and blade edge close, then filed it, then filed somemore, then sanded from 60 to 220. Heated to non-magnetic, oil quenched in warm motor oil. Heat treated at 375 for 3 1/2 hours, then soft-back drawed the back edge to a gun-metal (full color run), making the blade look awesome with the heat treat color, and my back draw colors. Had my elk taper drilled, guard and butt filed to hammer-fit. Had it all to fit togther seamlessly. Went to pein on the butt peice, got 2 measly strikes with a 3 ounce pein, and the tang sheared around 3/4 of an inch from the end. Really small grain, had the same grain as a peice just like it had been over-flexed back-and-forth multiple times until the bend snapped. Any help on why it broke other than "its a file"? I've worked with a few files like this before (exact same size, shape) and never had a break, could it have just been flawed steel?

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On a hidden tang, I always put my blade into a can of water or wet sand and draw the temper waaaayyyy back on the tang with a MAPP torch.

As you already hinted though, a file can always have pre-existing flaws, so it's hard to tell.

Don't despair... just cut the tang back a bit and braze some more length to it.

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Personally I would have tempered it at around 450 for about 2 hours and gone from there, depending on the thickness of the piece. It sounds like you got it to hot from the heat treat judging from the grain size.

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Very possible. Just means I can fire up the forge and re-harden a few blades while that ones annealing. 540 for 2 hours, then the back draw

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When steel breaks like you described it is hard and not tempered to a point where you could hit it or maybe even ujse it as a knife...A lot of folks know this as it is part of our own learning curves. Files are youir friends, A file sill skate on a hardened blade done right, and should try and cut on that has been tempered. Every part of the piece!

And I hope that is a typo on the temp you just posted? lol

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I don't know if you do this but I always anneal the whole blade before I harden the blade. When I harden the blade I only heat the blade, I try to keep the color out of the handle.

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I am sure you did, and there of couirse may be another answer to this,,but wot you describe is a piece of metal that was hardened and hit. If it had been tempered it wouild have either bent and could have been bent back, or it may have bent and then broke. Again a file will tell you more than we can in print.. if a good file skates and does not cut into the metal it has not been tempered enough to use as a blade. If yoiu would like to send me the pieces i will rockwell test them and give you the pieces back with the results,

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Its easily filable. From the grain where it broke and the method that it broke in I think it might have been a flaw in the steel. It may have been too soft to. It did flex the tang a tad. (enough to make it really hard to get out of the handle)

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I had already ground the broken peice down to braze/weld another peice to. Upon attempting to get the peined peice out, I observed what looked like the steel had been twisted. Took it out their was a visible seperation of the tang like it had been stamped incorrectly. The grain looked like a peice of stock that had been twisted while hot around onto itself and not fused

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Out of curiosity, was the bit that broke originally part of the rat tail of the file?

I've found these to be damaged on several occasions before.

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I usually cut the rat tail off, and draw out some fresh steel when using a full length file blade.

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