need help from knife maker

[Colossus]

I made a knife out of old file.
Last night i tried to harden the steel. Made sure the magnet wasn't attaching to steel before cooling. I cool it in water.
Not sure why but it's still not hard. I used an other file and i can take some metal out.

Any one can help out?

 

[rOmiLaYu]

Did you quench it in oil?

 

[Colossus]

First time was in oil. still not hard enough.
Second time in water, still not hard enough.

 

[rOmiLaYu]

First time was in oil. still not hard enough.
Second time in water, still not hard enough.

How hot did you have the steel?

 

[Colossus]

hot enough so that the magnet wouldn't attach.

this is before me trying to harden it.

 

[Wolf six]

I used another file and i can take some metal out.

Files are made to remove steel. You should be able to file metal out of it with another file.

 

[Fatzombie]

Some steels need precision temperature control and soak times. Being a file it probably does not. However without knowing what type of steel it is you are in a predicament. You cannot know for sure what is the best temperature / soak time and quench medium gives the best results. The manufacturer of the other file did and it is likely you will not reach the hardness of the untouched file without extensive testing. The good news is that you should get good results for a knife anyway because you don't want it to end up as hard as a file or it will be brittle like a file. While it is true water can be used to quench it is not always the best quench method. It boils rapidly and creates a gas shield around the hot steel that actually slows cooling in the first fractions of a second when you need the quenchant to be carrying heat away. For the best results you need a fast quenching oil like parks 50 or fast quench from McMaster Carr. If you insist on using motor oil or some other type of peanut oil don't expect as good of results. That being said you can get acceptable results from those types also but you need to make sure your other stages are correct. Using a magnet is a good start but once it is non magnetic let it soak for a minute or two longer to make sure it is all the way through and has enough heat to still be non magnetic on its way to the quench tank (hint: when steel is that hot it loses heat very rapidly when you pull it out of the forge). Get it to the quench tank FAST. Put it in tip or edge first and move it back and forth to cycle the oil but not side to side as this can cause warping. 20 or thirty seconds should do it but you can go longer if you want. You should have an oven ready to temper right away. BTW if you did not normalize he steel between your last efforts of trying to quench in oil and then trying to quench in water then you wasted your time. If steel does not harden when you quench it then you need to erase that mistake by normalizing before you try again.
There is more information on heat treating than you can read in a lifetime on the Internet. You will easily find information refuting anything I have said. I am by no means an expert but the basis of what I have told you works for me. Except that I only work with known steels.

 

[Colossus]

thank you.

That's the information l was looking for.

Yes, I knew the risk with the unknown file. It wasn't Nickolson too. But the file was cheap and very thick. Plus this is the first time I done a knife. So I took it as a learning experience. With the hope that something will come out of it.

Since the steel wasn't normalized between quenching. Is it why it won't harden? or it's just back piece of steel?

Everyone online uses oil for quenching. Now i might have to look into the McMaster quenching oil.

What I want is to make some knifes for my self.

 

[Fatzombie]

If I remember right they sell two kinds of quenching oil. Buy the faster one. If you need steel I've found that New Jersey Steel Baron has great prices and quality steel. I strongly suggest you start with 1075,1080 or 1084. These steels are easy to treat and very forgiving. I started with more technical steels because I thought they would make better knives. Even though I had good results I started using the high carbon steels like the 1084 and later and had more fun because they were easier and I could focus more on design and other skills. When you put a lot of work into a blade and have it fail in the hardening step it sucks!
I thought about it some more with your first file knife and I realized you probably did not anneal and normalize before your first heat treat either. This is likely your failure point. Read more about annealing and normalizing if you want to keep using files. If you order steel from a knife supply house or steel manufacturer it already comes annealed and you can skip that step. You may be able to skip normalizing if you do stock removal method but some people still suggest it.

 

[Colossus]

looks like i need to do more reading.