# Knife blade from a chisel- what do I need to know?



## TRfromMT (Jan 18, 2016)

Guys,
I have an old chisel that the handle is cracked and in need of replacement. I have other chisels so I am contemplating turning this thing into the blade for a knife. I want to put a tanto point on it, and sharpen one side. This will take a lot of grinding...

Some questions -

Will this destroy any temper / hardness in the blade? Do I need to keep it cool during grinding (is that even possible)?

Should it be heat treated after grinding? I am not set up to do this, so is there a poor-man's heat treating method (I'm thinking propane torch and a bucket of oil)? Is there something you can point me to on the web?

This is just a simple project to make a shop knife. I'll put a knife handle on it after re-grinding. Just wondering how dumb this idea is....


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## NYWoodturner (Jan 18, 2016)

@robert flynt or @Foot Patrol or @therichinc would be able to give a more direct answer, but my guess is you will have to annual it before re-grinding and the re-heat treat. Knowing what kind of steel it is will be paramount to the success of the knife so I'd start by researching the brand chisel and what type of steel its made from. I would guess though that you could make a good knife out of a chisel.


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## robert flynt (Jan 18, 2016)

It is hard to explain but with experience you can check the hardness with a file. When full hard a file will skate across a sharp edge of the metal. If it is soft the file will bite in to the metal easily. If it is about right it will cut the metal but not easily. You can grind the chisel as is but you must keep it cool by plunging it in water after each pass then wipe it off with a rag, not get the metal so hot it goes past a straw color. If you anneal it you have to get it to critical temp. ( a temp. where a magnet will not stick to it ) then cool it very slowly by sticking it in vermiculite or wood ash. When you harden it you must heat it evenly and hold it at critical temp, a bit then plunge it a very thin oil like vegetable or peanut oil which has been preheated to 125 deg. .After this the file should skate across a sharp edge and it is time to clean it up and put it in an oven at 375 to 400 deg. for 1 hr. , do this twice. By the way, I don't think a propane torch will not be able to keep it evenly heated at critical temp. You can test it by putting an edge on the blade then chopping deer antler a an angle. If it's to hard the edge will chip if it is to soft the edge will curl. Good luck and have fun!

Reactions: Like 3 | Informative 1


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