Youtube is a beautiful thing. Now! When I first started making knives there was nothing on Youtube about knifemaking. I had to figure things out for myself. Well... I ended up buying five books on blacskmithing, bladesmithing, and knifemaking. And I learned a few things along the way.

And when it comes to knifemaking I learned one very important lesson. And it is something you should keep in mind if you are embarking on the journey of making a knife or of knifesmithing.

The lesson is that The heat treatment is everything. It is the all consuming and all important thing.

We tend to pay a lot of attention to the look, the curves and the aesthetics of a knife. And this is all very important. Along with the grip, feel and fit of the knife. But the hardening and tempering of the blade trumps all that. This is why.

A knife is a cutting instrument. That is it's ultimate purpose, it's raison d'etre or reason for being. And getting a sharp edge on a knife is great. It's important. But there is more going on there. It isn't just about sharpness. It is about a technical term called "toughness" . This is the characteristic where it will hold it's edge without dulling or chipping, while still being able to take pressure and use.

The balancing act

So, when it comes to the edge of a knife there is a balancing act that goes on and it has to do with the characteristics of steel.

You can harden steel a whole lot. You can get it very very hard. And when it is that hard you can get an amazing edge on it. It will be very sharp!

But, when steel is that hard it is also very easy to chip, break or even shatter.

And you can soften the steel. Which means it will have some flexibility and give in it. So when you apply pressure on it during use it will not shatter or chip. But.... it will not hold an edge very well. It will blunt quickly.

So. you have to find the sweet spot for the edge of the knife. It has to have a certain hardness and a certain softness. And in that sweet spot the knife will be hard enough to hold a great edge and soft enough to be durable and not bluntable.

How do we do this?

This achievement of toughness is done in a two step process called Hardening/Tempering.

You first harden the knife to a very hard condition. You do this with heat. A lot of heat! Then quench it and let it cool. Then you soften it up in a process called tempering. In this process you heat it just a little bit. This softens it enough to be tough. yet still holding it's edge.

There are variations you can use. For example, and this particularly applies to long/big knives and swords, where you harden just the cutting edge of the knife so it holds it's edge. And you soften the back end of the knife (the spine) so it has some flexibility and give.

You can see this exact process of hardening/tempering in my youtube video on knifemaking. This is Part 2 of my tutorial on knifemaking for beginners: Knifemaking Tutorial Part 2 of 2 You can watch that video below.