Newbie file knife

B

Biagio

Joined
Apr 12, 2022
Messages
6
Hello, I'm planning on making a knife from some old good quality Nicolson files. Should I tenper them in the oven now for 1 or 2 hours at 400 or after I have a good rough shape and grind on the blade? I've watched videos of people doing it before and after. To me it would make more sense to do it before that way it's easier to grind. I don't have a forge so I don't want to quench it or anything like that. I'm new to this so please keep it simple. Thank you very much
 
Biagio said:
Hello, I'm planning on making a knife from some old good quality Nicolson files. Should I tenper them in the oven now for 1 or 2 hours at 400 or after I have a good rough shape and grind on the blade? I've watched videos of people doing it before and after. To me it would make more sense to do it before that way it's easier to grind. I don't have a forge so I don't want to quench it or anything like that. I'm new to this so please keep it simple. Thank you very much
Click to expand...
 
Last edited:
I think you should take a look in the knifemaker's section of the forum, it has loads of great info.

I'm not sure you know the steps to knife making. You temper a blade to reduce the stress caused by the hardening process, so the file was tempered by the manufacturer a long time ago. If you want to avoid having to harden your knife, you can try and grind the file as is and try to keep the metal from getting too hot, but tempering it again would just remove that hardness. This is really the only way to do it without a forge/HT oven to reharden the steel.
 
I appreciate the info. In the videos I've watched they say putting the knife in the oven helps to bring the hardness down so it's no so brittle. Does that make sense?
 
It sounds like you’re describing a step called normalizing, which removes much of the internal stress from the steel and makes it easier to grind and shape. Annealing removes even more. After grinding to 80% shape or so, many makers reharden the blade, temper it to gain a balance between brittle and tough, then do their final grind.

Grinding a file into a knife while retaining the original heat treatment is going to be a long and tedious process. You’ll need a light touch and don’t let it turn blue. This will be particularly difficult when grinding the thin edge profile. If I was so inclined, I’d start with what’s called a knife-edge file (kinda wedge shaped in cross section).

You’ll make it much easier on yourself, and improve your finished product, by figuring out a way to reharden and temper after you grind to shape. In a pinch, I’ve done it with a welding torch. Not ideal, but possible.

Parker
 
If you heat file steel to critical temp and quench, you will have 62(?) Rockwell. Harder than woodpecker lips, but brittle. Files are about 62. I've seen them break when dropped.
1095 knife steel is about ~ 52-58 Rockwell. Only way to get that with carbon steel is to harden to full hardness and then temper to a lesser Rockwell.

Grinding a file into a knife without re-hardening is a long, difficult process. You'll take the hardness out grinding easily.
I've seen people do it. They would come into work every day and grind a little before work, quenching often. Took them a while.
 
There are two ways to do it:
1) make the steel full soft, work it and reharden
2) soften it a bit to final hardness.

Sounds like you want to try option 2.
Then soften a bit and shape into a knife. Don't overheat or you'll ruin the ht and the knife won't hold an edge.

I prefer option 1 but you need to reharden
 
Last edited:
Here is a previous thread I wrote:

How to Make a Knife From a File

This is a basic tutorial for making a knife from a file. The process of knifemaking is discussed in many of the other stickies, and this tutorial will only deal with the basics. For more detailed info on making your first knives, see the sticky, "How to Instructions for Making a Knife". For...
www.bladeforums.com www.bladeforums.com
 
So I got my shape out and it's where I want it. I kept it very very cool and I was able to hold it the whole time no issues and I kept dropping water on it. I'm super bappy with it. How long should I temper it in the oven for? Should I try at 380 for an hour first then let air cool? Then try a higher temp a second time on another cycle if not satisfied? Thanks
 
425°F for two hours.
Take out and cool off in water.
Put back in for two more hours.
Cool off in water.
Finish sanding and sharpen.
 
You must log in or register to reply here.
Back
Top