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too hard


stangcrazy85

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so i am new here and thus far i'm loving it
anyhow i used a nichols medium to large file for a knife blade tang and all
i let it get white hot and then cool ever so slow did all the grinding and shaping then got it hot in the forge thun plunged it in the used motor oil
that thing is soooo hard even old grandpa could barley get a edge on it said he had to hone the crap out of it
my question is why did it get so **** hard ????
im new to this so go easy on me

Edited by steve sells
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I'm afraid you're probably produced a dangerous knife on your first attempt. Heating to white is WAY too hot and grain growth will cause weakness. Not tempering it is another mistake that makes it brittle and liable to fail when you need it most.

Do a little reading and ask some questions before you make your next knife. In the mean time build fires and forge things from mild steel to learn the basic skills you'll need. Follow the "Lessons in Blacksmithing and Getting Started" sections.

Frosty

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When you quench a high carbon steel it comes out hardened and will often be as brittle as glass---drop it on concrete and it can shatter into pieces! It also has terrible stresses in it from the quench and can even break just sitting on a bench.

So as soon as you get a blade out of quench you *gently* clean it up and draw termper on it. Tempering trades some of the hardness for toughness making it easier to sharpen and also able to take use stresses without shattering in your hand.

Tempering temps are based on the alloy, quench medium, intended use, personal preference and is done BEFORE you put a handle/grip on the blade as the temps are usually too high for hilting materials.

You did read that BP on heat treating blades didn't you? Seems odd we should have to type all that stuff in again just for you.

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There are sticky's on proper ways to heat treat in the knife section, with links to references, and so there are more links in those, over 200 links all totaled...

Also by quenching such a very high temperature, you have created mostly Plate Martensite, rather than lathe, so it will be very brittle no matter how much tempering, compared to a proper temp. quench.

Read and try again. Never give up, never surrender!

Edited by steve sells
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Just out of curiosity, Is it possible to save a piece that is gone through this improper HT? I understand the handle would be sacrificed, but could one re-heat or normalize per say? Then re heat treat in a proper manner? OR is a piece permanently done for in this extreme over heat and quench?

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The wood handle can be salvaged if it was epoxied. All epoxies I work with soften around 150 degrees F. A good heat gun can do the job, but remember, wood is a good insulator so it takes time for the heat to migrate to the center - don't rush it with a high setting. Medium heat for long time is much better the HOT heat for short time.

After the handle is removes follow instructions to normalize, harden and temper.

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Note if you are going to re-heat treat the blade don't worry about soaking in heat through the wood handle, heat the blade with a propane torch till the epoxy gives out and then remove the slabs and re-heat treat the blade. (scraping as much gunk off the slabs while it's soft is a good isea too but be careful as it's hot!)

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Thomas, your responce is absolutely correct. I never gave any thought beyond removing the part that had been epoxied on. Now, if the blade was in excellent condition and you did not want to alter it in any way, my approach would work, or better yet, a common kitchen oven would do the job. I find myself removing epoxied fittings from objects that are to big for the oven and that's when I find the heat gun is my friend.

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