What constitutes a knife holding an edge?

[Fletch Helical]

I've always been curious about this but never really was able to figure out what's the differences between all the different steel types out there and what is the "best" material for holding an edge. I realize that the more extreme the edge the easier it will likely dull as opposed to an knife deisgned a bit more for working but not as razor sharp. (I guess an example would be something like a razor blade compared to a hunting knife).

So I'm curious as to what determines a knife holding a good edge. For example I'm looking at making my first knife in the future and I've heard that 1084 s a great metal to start with. It also seems that some people love O1 but what, if any difference is there between how well one holds an edge? Then how does that differ from something like D2 or S30V? Or someone here recently posted about looking for good kitchen knives and people seemed to think 440C was good. How does that compare to something like a knife brand like Henkel which is Soligen Steel?

I guess what I'm wondering is how does a person determine what steel is for what knife?.....If that makes any sense to anyone.

 

[JTknives]

I've always been curious about this but never really was able to figure out what's the differences between all the different steel types out there and what is the "best" material for holding an edge. I realize that the more extreme the edge the easier it will likely dull as opposed to an knife deisgned a bit more for working but not as razor sharp. (I guess an example would be something like a razor blade compared to a hunting knife).

So I'm curious as to what determines a knife holding a good edge. For example I'm looking at making my first knife in the future and I've heard that 1084 s a great metal to start with. It also seems that some people love O1 but what, if any difference is there between how well one holds an edge? Then how does that differ from something like D2 or S30V? Or someone here recently posted about looking for good kitchen knives and people seemed to think 440C was good. How does that compare to something like a knife brand like Henkel which is Soligen Steel?

I guess what I'm wondering is how does a person determine what steel is for what knife?.....If that makes any sense to anyone.

All i can say to this is that Experience is what will tell you what steel to use for each knife. there is not just one super steel that does it all, unless your talking about Don's W2 . you have to select a steel according to what the knife is going to be used for. Also edge retention is a factor of the environment that the knife is used in. some steels are better at holding an edge cutting cardboard then other steels but that steel might not hold as good of an edge carving wood as the other steel. so as you see you have to select the steel to match the purpose of the knife. Another thing that plays a huge roll in edge retention is the shape of the edge. these are all things you learn or gain with experience.

 

[Leu Custom]

What determines how good of an edge is held on a knife is the way the blade is heat treated.

If you want an AXE, obviously you won't use a slicer to do the job and the edge would most likely be convex or something like that with some MEAT with a steeper grind whereas a razor would not be used for chopping.

Also depends on what you're gonna cut.

 

[Nebulae]

are you saying, disregarding toughness completly, and corosion resistance as well? your not going to like this: obsidian. best steel CPM 121 @ 70.5 Rc but still brittle as glass. best compromise CPm M4 @ 65 Rc its still pretty tough, almost all of the national cutting competition blades are made from M4 because it can take a very thin edge angle (like 10 degrees) and at a competition your disqualified if the edge rolls or chips, so its also tough. heard it sharpens razor sharp pretty easily

 

[cotdt]

Like Nebulae mentioned, for holding an edge you want something that is both wear resistant and tough. Some steels are very wear-resistant, but loses sharpness by microchipping because they have poor edge stability. For example, 1084 at 65 rc is outperformed by S90V in rope-slicing tests, but in actual use cuts much longer because it is much tougher and can hold a thinner edge. It resists chipping far better even with the thinner edge.

Basically, forget what the numbers say. Actually use paints a different story.

 

[69_knives]

I've read that with a 5160 blade you should just expect to have to sharpen it every day or every time you use it. Again it depends on the use. I've made a couple axe-like choppers out of 5160 and they cut through wood like nobody's business and are still quite sharp, shaving sharp actually afterwards. But, on a thinner edge, yes, expect to have to sharpen it regularly. A couple swipes on a 220 - 400 stone is not unreasonable and should give it a nice toothy edge that will keep it cutting for as long as there is steel left on the blade.

 

[Karl B. Andersen]

I've read that with a 5160 blade you should just expect to have to sharpen it every day or every time you use it.

Not true.
I field dressed, skined and quartered 11 deer last year with my STILL hair shaving sharp 5160 hunter.
I intentionally did NOT sharpen it, so as to see if I can get through another year.

 

[69_knives]

Not true.
I field dressed, skined and quartered 11 deer last year with my STILL hair shaving sharp 5160 hunter.

That is impressive performance, sir.

 

[nullack]

It is a function of strength, toughness, hardness, wear resistance and the dimensions of the blade.

 

[Nebulae]

ha ha, I just reread your original post, is your question what properties (wear resistance, toughness, corrosion resistance) are best for what applications? you must understand that all of these are trade offs. the 440s are used for kitchen knives b/c of its corrosion resistance its really not good germ wise to cut raw meat with a rusty and pitted knife. smaller knives for realitivly delicate purposes can be made from steels with good wear resist, and corrosion resit but less toughness, or confusingly could be mad from a steel with good toughness, and ground thinner to cut better

 

[Fletch Helical]

Well as of right now my short term goal is to make a good hunting knife I can take in the field. Something capable of field dressing a deer with ease and not require a re sharpening every other deer. I would also like to eventually make a good skinning knife. And at some point even further on down the road perhaps make something like a tactical/utility knife (either a folder or fixed). Which would be an "all around" knife similar to an everyday carry that would be used for anything and everything that people use an EDC for.

But for now any fixed blades I plan on making would be for a hunting/field use. But would the say the differences between the blades of say those 3 types of knives still vary quite a bit?

Basically I have a thing with knives that anyone I've ever had I like to be shaving sharp. Now they were all just knives I bought from manufactures and some naturally hold edges better that others. So I guess like someone mentioned I may be looking for a "magical" steel that is razor sharp and can "do it all". Which obviously is non-existent, I guess as of right now all my experience with knives has been with what I've bought, which naturally I guess I'm going to run the gamut as to which ones outperform others I was just trying to figure out what makes some steels "better" than others when it comes to the ability to take and hold an edge, and what would be suitable for what I'm looking to hopefully make.

 

[sunshadow]

I've read that with a 5160 blade you should just expect to have to sharpen it every day or every time you use it. Again it depends on the use. I've made a couple axe-like choppers out of 5160 and they cut through wood like nobody's business and are still quite sharp, shaving sharp actually afterwards. But, on a thinner edge, yes, expect to have to sharpen it regularly. A couple swipes on a 220 - 400 stone is not unreasonable and should give it a nice toothy edge that will keep it cutting for as long as there is steel left on the blade.

5160 is probably the most commonly used steel for JS test knives because with the proper HT and geometry you can attain and keep a seriously sharp edge through a variety of cutting tests and still pass the flex test. If your 5160 blade is not capable of holding an edge through use examine your HT and geometry.
There are many poor choices of HT that have come into common use by some extremely well known makers and been emulated by others that can give perfectly good steel a bad reputation

-Page

 

[Nebulae]

so the way I see it theirs too groups of steels. the stainless with good corrosion resistance, and the carbon with good wear resist, and toughness. So if you can take care of your knives get carbon, if you cant you dont deserve good steel. howeve ther are some new bridgeing steels that provide some of both CPM s30v for one I would sugest if CPM M4, because at 63 Rc it is still very tough, and super wear resistant because of the tungsten and vanadium carbides. most carbon steel If heat treated correctly will get a charp edge and hold it pretty well.

 

[cotdt]

Well as of right now my short term goal is to make a good hunting knife I can take in the field. Something capable of field dressing a deer with ease and not require a re sharpening every other deer. I would also like to eventually make a good skinning knife. And at some point even further on down the road perhaps make something like a tactical/utility knife (either a folder or fixed). Which would be an "all around" knife similar to an everyday carry that would be used for anything and everything that people use an EDC for.

But for now any fixed blades I plan on making would be for a hunting/field use. But would the say the differences between the blades of say those 3 types of knives still vary quite a bit?

Basically I have a thing with knives that anyone I've ever had I like to be shaving sharp. Now they were all just knives I bought from manufactures and some naturally hold edges better that others. So I guess like someone mentioned I may be looking for a "magical" steel that is razor sharp and can "do it all". Which obviously is non-existent, I guess as of right now all my experience with knives has been with what I've bought, which naturally I guess I'm going to run the gamut as to which ones outperform others I was just trying to figure out what makes some steels "better" than others when it comes to the ability to take and hold an edge, and what would be suitable for what I'm looking to hopefully make.

Actually, any steel with more than 0.5% carbon can do that. You can field dress deers for weeks w/o having to resharpen, maybe with touchups every once in a while. The heat treating is very important though. Unfortunately most supermarket knives are heat treated very soft and won't hold an edge for long, and they can't take an acute edge that is good for cutting.

I don't think there are any bad steels. Even the more brittle stainless steels that chip during hard use, you can still cut with them just fine. Well, if you want stainless, AEB-L is very tough and can hold an edge. The steel is used for razor blades and are designed to get really sharp.

 

[Ed Caffrey]

Reading the posts in this thread, I believe that something is missing. I'm assuming that your basing your initial question on your experiences with production type knives? If thats so, then what must be realized is this...generally there is a huge difference between a factory/production knife, and one made individually by a competent "custom" knifemaker...even from the exact same steel type.
What differs is this... A production knife company will generally think along the line of: How cheaply can we produce a product, to a minimal level of quality that the public will purchase, and obtain the maximum profit for the given item. If one of their knives happens to fail, there is no one individual that you can point a finger at, and usually they will just send you another knife off the same assembly line. Thats not a jab at any production knife company, just the cold hard facts.

On the other hand, because a "custom" knifemaker is usually a sole individual, who's name goes on each and every knife produced, each and every knife that leaves his/her shop MUST be the very best it can be, not just "good enough". This means the "custom" knifemaker will take the same blade steel as the factory, study it, research it, and test it, seeking improvement, until he/she achieves the maximum performance they can with the given steel. What this means is that as a general rule, you will acquire a much better overall knife from a "custom" knifemaker versus a factory knife, even if both are of the same blade material.

OK, now that I've said all of that, a superior preforming knife includes a huge number of variables that I choose to call "The overall package". Its not something that is achieved overnight, nor easily, but with concerted effort and hard work, usually over a long period of time, its very achievable. An example is Karl's post about 5160. Karl has taken a great deal of time and effort to develop that steel, and can achieve things with it that many other may not be able to. The same efforts Karl has put into 5160, I've put into 52100. The experiences Karl relayed the durability of 5160 are similar to what I would say of 52100.
As has already been stated in many of the posts on this thread...your going to have to decide what characteristics are important to you. With steel its always a give and take scenario. Stainless qualities will generally mean the blade will be more brittle than a carbon steel of the same carbon content, and so on. Knowledge is the key to either building or buying the perfect knife...for you.

 

[Troop]

Not true.
I field dressed, skined and quartered 11 deer last year with my STILL hair shaving sharp 5160 hunter.
I intentionally did NOT sharpen it, so as to see if I can get through another year.

:thumbup: I'm getting similar (ballpark) results with my 5160. Like Mr. Caffrey is saying, you have to learn how to develop it.

 

[Fletch Helical]

Reading the posts in this thread, I believe that something is missing. I'm assuming that your basing your initial question on your experiences with production type knives? If thats so, then what must be realized is this...generally there is a huge difference between a factory/production knife, and one made individually by a competent "custom" knifemaker...even from the exact same steel type.
What differs is this... A production knife company will generally think along the line of: How cheaply can we produce a product, to a minimal level of quality that the public will purchase, and obtain the maximum profit for the given item. If one of their knives happens to fail, there is no one individual that you can point a finger at, and usually they will just send you another knife off the same assembly line. Thats not a jab at any production knife company, just the cold hard facts.

On the other hand, because a "custom" knifemaker is usually a sole individual, who's name goes on each and every knife produced, each and every knife that leaves his/her shop MUST be the very best it can be, not just "good enough". This means the "custom" knifemaker will take the same blade steel as the factory, study it, research it, and test it, seeking improvement, until he/she achieves the maximum performance they can with the given steel. What this means is that as a general rule, you will acquire a much better overall knife from a "custom" knifemaker versus a factory knife, even if both are of the same blade material.

OK, now that I've said all of that, a superior preforming knife includes a huge number of variables that I choose to call "The overall package". Its not something that is achieved overnight, nor easily, but with concerted effort and hard work, usually over a long period of time, its very achievable. An example is Karl's post about 5160. Karl has taken a great deal of time and effort to develop that steel, and can achieve things with it that many other may not be able to. The same efforts Karl has put into 5160, I've put into 52100. The experiences Karl relayed the durability of 5160 are similar to what I would say of 52100.
As has already been stated in many of the posts on this thread...your going to have to decide what characteristics are important to you. With steel its always a give and take scenario. Stainless qualities will generally mean the blade will be more brittle than a carbon steel of the same carbon content, and so on. Knowledge is the key to either building or buying the perfect knife...for you.

Wow very solid post!! Thank you, gave me some good insight into what to really think about and look for.

And you are correct I've never really had a custom made knife. It has always been looking at production knives. Had I taken the route of getting a few custom made knives early on I probably would've saved more money than going from one knife to another....(Then again maybe not I will likely always see one that I ooh and ah over and want ).

Now I'm getting into getting ready to try my hand at making my own so naturally I have a gazillion questions. I'm just trying not to flood the forum with all of them at once. Plus when I'm actually ready to order the steel and get started I'll likely have even more questions.

 

[Nebulae]

...generally there is a huge difference between a factory/production knife, and one made individually by a competent "custom" knifemaker...even from the exact same steel type.
What differs is this... A production knife company will generally think along the line of: How cheaply can we produce a product, to a minimal level of quality that the public will purchase, and obtain the maximum profit for the given item. If one of their knives happens to fail, there is no one individual that you can point a finger at, and usually they will just send you another knife off the same assembly line. Thats not a jab at any production knife company, just the cold hard facts.

he's right, but I might add that another reason facotory knives are under hardened, is because you cant really blame them for making a crappy knife that doesnt cut, but if they did mass produce very hard knives, the general public would brak allot more of them, and possibly hurt themselves, causing the manufacturer to at least have to deal with a bunch of crap, refunds, and maybe even lawsuits

 

[cotdt]

I realize that the more extreme the edge the easier it will likely dull as opposed to an knife deisgned a bit more for working but not as razor sharp. (I guess an example would be something like a razor blade compared to a hunting knife).

The thinner edge actually lasts longer. This has been widely documented.

And +1 to custom knives. Custom knives run circles around production knives made in the same steel. There have been some rare exceptions though, with some recent Spydercos that have been heat treated very well.

 

[nullack]

It all depends on how a production knife is:

1. Controlled for material quality
2. Controlled for heat treating
3. Controlled for machining

There is no magic that a bloke in a custom shop can do that a manufacturer of a production knife cant. And in a custom shop, there very well might be more chance for errors in heat treating or machining errors for example than a pro setup where its done using CNC and computer controlled heat treating.