Knife Blade Quality Chart

[Lynx]

Hi Guys,

This is my first post and I am trying to get my head around the different quality ratings for knife blades. I must admit up until recently I thought a knife blade was made of metal and was either sharp or blunt at which stage you sharpened it! It appears there is a lot more to it that and so I wondered if someone could link me to a site that possibly had a chart showing all of the different strength ratings from the very best at the top working down to basic stainless steel or suchlike. This will help me to determine the best quality blades when choosing a new knife. Any help will be greatly appreciated.

 

[8thsinner]

There are hundreds of sites with information on this.
I just found another good one this week about sharpening methods, steel compositions and reviews. It's quite in depth but also pleasant to read and it will give you a good start to understanding the importance of heat treating good steals.

http://www.zknives.com

 

[Ph34r]

As far as i'm aware there is no such site. But i offer a simple a level chemistry explanation.
The more carbon there is in the steel, the stronger (and more brittle it is)
stainless steel is just an alloy of iron, which has carbon and chromium in it - the chromium prevents the rusting to occur.
Ultimately, it is your choice:

High carbon steels are easier to sharpen, and hold an edge better - but rust unless oiled regularly.
Stainless steels take longer to sharpen, retain an edge reasonably well, and do not rust as quuickly.

hopefully my addition to this thread will attract a steel buff - who will be able to tell you a bit more - or if not, head over to brtish blades, and post there:
http://www.britishblades.com/forums/forum.php
Hope this is helpfull,

Ph34r

Post script: carbon steels allow you to do things that stainless ones do not ( i.e. producing a spark when scraped against flint)

 

[merman]

It is the Chromium oxide that make the stainlesss steel shiney, but it should be polished as stainless suffers from crevice corrosion under anarobic conditions. There are about 40 different grades of stainless steel alone.

Steel can be a fairly in depth and complex subject, (very simply)higher amounts of carbon and other impurities (eg chromium) make atomic dislocation harder therefore the steel stiffer, differing alloying impurities and heat treatment / cooling / % cold working, etc give a vast range of different propities to the steel.


Hypoeuctectiod steel contains pearlite and ferrite and has < 0.8% carbon at room temp.
Eutectiod steel contains pure pearlite and has an 0.8% carbon content.
Hypereutectoid steel starts to contain cementite and pearlite and has > 0.8% carbon content.
Looking at samples under a microscope and calculating ferrite / perlite / cementite percentages tells you the carbon impuritiy amounts, the size, shape and alignment of the crysitline grain boundries tells you about how the steel has been cooled or worked, these all combined with testing can give the mechanical propities of the material.

Here is a site I found whilst studying my engineering degree a while ago.

http://www.steeluniversity.org/content/html/eng/default.asp?catid=115&pageid=2081271922

http://www.steeluniversity.org/content/html/eng/default.asp?catid=4&pageid=1016906230

I am sure there are others that can give more digestable and useful advice on the type of steel needed for knife blades and how to simply test for this. I am always in awe of the way traditional blacksmiths understood and still practice the metaulargy behind metals without knowing about atoms, crystals etc.......

 

[Lynx]

Thanks for your replies. A lot of time has spent on answering this and I do appreciate it. I am back to work today but will look up the links etc later and start to get my head around it all. Thanks again.

 

[8thsinner]

As long as you realise you will never actually get your head around it, you will simply understand more than others might...
There is probably a thousand great master blade makers out there, and every one of them uses different steels and tempering methods and they all got to that end searching their own way. Discovering it's the BEST method for that particular use.

Welcome to the search for truth...

 

[Lynx]

During my search to better understand knife making, the metals used and the ratings I came across this site which manages to explain everything in laymans terms and was just what I was looking for. For the benefit of others here are the links:

http://www.knife-making-supplies.net/rockwell-hardness-scale.html

http://www.knife-making-supplies.net/knife-steel-basics.html

http://www.knife-making-supplies.net/knife-steel-basics-2.html

I think this sort of explanation should be posted on every knife site!

Thanks again to everyone for their help.

 

[ged]

...I am trying to get my head around the different quality ratings for knife blades. ... from the very best at the top working down to basic stainless steel or suchlike. This will help me to determine the best quality blades when choosing a new knife.

People use the term "quality" to mean different things. Manufacturers use it to mean "it's what we say it is". Quality control is about making sure that what a manufacturer makes is what they intended to make, and that it reaches the customer in the condition in which it was supposed to reach him. You might have a very high quality tool that is totally unsuited to the task. That doesn't make it a poorer quality tool, that makes it a bad choice for that application.

Th Zknives site has already been mentioned but there wasn't a direct link to this particular page:

http://www.zknives.com/knives/articles/knifesteelfaq.shtml

It's worth looking at if you haven't seen it already. It makes my head spin.

It should be obvious by now that there isn't a "best quality" blade steel which you only buy if you can afford it and which will be the answer no matter what the question is. There are different steels for different tasks, for example if you're diving in the Red Sea you won't choose a knife that's made of O1. My wife's diving knife is about as sharp as me but it's a lot less rusty. And it doesn't end there, because things like heat treatment can be just as important as the material that you start out with. Then you have shape, grind etc. which can mean the choice becomes very difficult and you'll probably just end up getting one that you like the look of. Then another. And another...

If I were buying a stainless blade, personally I'd be looking at the more modern steels. Technology seems to have moved them on quite a way in the last decade or so. Steels which aren't considered stainless don't seem to be getting quite so much attention, so if you won't be worried by rust (either because you won't be letting the blade sit around wet or because you don't mind doing a bit more work to maintain it) then there are a few stalwarts like O1 (or one of its dozen or so other names) that will give you very good service. You can make a serviceable knife from an old industrial hacksaw blade. There's been one in my tool box for about 40 years. There are guys here who would probably laugh out loud if they saw it, but it will easily cut through a steel coat hanger without being damaged, I don't care how much it gets scratched by the other tools in the box, and it's always there when I need it. I wouldn't dream of putting something that cost a few hundred pounds in there to replace it -- most likely it wouldn't be up to the job anyway.