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Author Topic: Knife forge/quench problem  (Read 1827 times)

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Offline sleek

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Knife forge/quench problem
« on: August 10, 2016, 12:14:35 am »
So I am hardening a large 7 inch blade. I get it hot and stick it tip first in the soap water quench and the blade is warped when i pull it out. Its warped sideways, as if i layed it on it side and dropped it in the quench. A straight blade is important. What could be the problem?
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Offline bubby

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Re: Knife forge/quench problem
« Reply #1 on: August 10, 2016, 12:51:12 am »
What kind of steel is it and did u warm the quenching agent
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Offline sleek

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Re: Knife forge/quench problem
« Reply #2 on: August 10, 2016, 01:03:40 am »
Its a file and no I didnt warm it. Its been outside all day, probably was 90 degree water.
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Offline osage outlaw

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Re: Knife forge/quench problem
« Reply #3 on: August 10, 2016, 06:49:16 am »
I've read and heard that quenching in water can warp a blade.  I use oil and warm it up before the quench.  From my research that seems to be the most recommended method.
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Offline JoJoDapyro

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Re: Knife forge/quench problem
« Reply #4 on: August 10, 2016, 09:53:08 am »
I quench in Brake fluid.
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Offline Ed Brooks

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Re: Knife forge/quench problem
« Reply #5 on: August 10, 2016, 10:01:06 am »
from a know nothing but what I've seen on here or on the boob tube, kinda point of view.  I've seen them mention that you want your blade facing true North when you quench it. because of it being magnetized when you heat it. From the opinion of you knife makers is there anything to this?
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Offline osage outlaw

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Re: Knife forge/quench problem
« Reply #6 on: August 10, 2016, 10:11:15 am »
I've heard that from 3 different sources Ed.  I don't know if there is anything to it or not but I've started doing it.  I figure it can't hurt.
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Offline Urufu_Shinjiro

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Re: Knife forge/quench problem
« Reply #7 on: August 10, 2016, 10:22:50 am »
I've heard that too and as the others I can't confirm the science of it but the folks I've heard it from all said that their knives warped to the side until they tried it facing north and the problem went away. While correlation is not causation it does carry a little more credence that they didn't believe some old wives tale out of hand, only after it worked for them.
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Offline E. Jensen

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Re: Knife forge/quench problem
« Reply #8 on: August 10, 2016, 11:12:42 am »
Haha north has nothing to do with it.  Couple things to look for.

How are you agitating in the quench?  Side to side or up and down?  Obviously side to side will cause warping.

How many times are you normalizing?  Preexisting stress in the steel will cause warping.

Even if you do everything right, blades warp.  Best thing to do is to learn to unwarp them.  Go ahead and temper the blade, then grind enough to expose fresh steel.  Put the blade in a vise with 3 large pins so that it's being bent a little past straight, then gently torch till it turns brown (no hotter).  Might take a couple tries but you'll get there.  It's also possible to grind a blade straight if it's not too severe, but that is a bit more advanced.
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Offline HickoryBill

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Re: Knife forge/quench problem
« Reply #9 on: August 10, 2016, 11:58:07 am »
What kinda file is it and how old is it?
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Offline bubby

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Re: Knife forge/quench problem
« Reply #10 on: August 10, 2016, 02:33:41 pm »
I've quenched in water but i use canola oil and warm it on a hot plate , normalize 3 times then heat treat and quench
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failure is an option, everyone fails, it's how you handle it that matters.
The few the proud the 27🏹

Offline sleek

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Re: Knife forge/quench problem
« Reply #11 on: August 10, 2016, 07:31:31 pm »
Its a save edge usa farriers rasp. I did multiple heats and cools. I dont know its age. I will go ahead and put it in the oven to draw its hardness down, then put it in a vice to straighten it. Hopefully it doeant snap. Here is a pic of it. Should I just anneal it again and start over?

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Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline sleek

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Re: Knife forge/quench problem
« Reply #12 on: August 10, 2016, 07:33:24 pm »
I did however get some great forge pics!



Fired up and laying a bed of hot osage coals



A heat gun really lays on the oxygen



This last pic shows the knif spine, blade down in the coals.



And the soap water quench

« Last Edit: August 10, 2016, 07:37:25 pm by sleek »
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Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline cantshoot

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Re: Knife forge/quench problem
« Reply #13 on: August 10, 2016, 11:45:34 pm »
Awesome pics! Forging knives and axes is a dream for future years... One day :)
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Offline bjrogg

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Re: Knife forge/quench problem
« Reply #14 on: August 11, 2016, 07:41:38 am »
Really nice pictures sleek. Better than a campfire
Bjrogg
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A hot cup of coffee and a beautiful sunrise
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