Blade steels - what's wrong with improvement?

[Ankerson]

My neighbor needed it and he's a heck of a nice guy.

OK, very cool and nice thing to do.

 

[me2]

And something for the Science guys to chew on.

What if the Roman Empire either never fell or all of that Technology wasn't lost and or suppressed for over a thousand years...... Narrow Minded thinking did all of that..... No Advancements........ Everything went backwards...... People of Science were killed and or burned at the stake for being witches..... Also known as the dark ages.........

Think about were the human race would be today compared to were we really are currently....

Now that makes ones head spin....

It would be like jumping a thousand years into the future as far as science and the way of life is concerned......

So you would think that people of Science would be finding ways to improve technology instead of suppressed it......... Just some food for thought.

You people are supposed to be the smart ones in the room with the big brains looking to improve things and make things better.

And some seem to working really hard at suppressing any new technology when it comes to the steels..... When as scientists you should be working to improve on it or find advancements.......

Or are just they just like the common folk of the past.......

I knew that wasnt it when I read that post the first time, before the dig was added. No one is suppressing anything. Thats just silly. If anything, they (we) are adding information. Its not widely known that edge angle has a large influence on cutting ability and edge retention. There are applications where modern CPM high wear alloys are not optimal. Those applications have been stated several times in other threads like this. Low edge angles, high polish, hard contacts or impacts, relatively strong materials (wood, plastic vs rope, skin, meat), and when a high sharpness is desired/required. Moderate to high edge angles, coarser finishes, relatively soft, abrasive materials, and tolerance for lower sharpness all favor modern high wear alloys.

 

[Ankerson]

I knew that wasnt it when I read that post the first time, before the dig was added. No one is suppressing anything. Thats just silly. If anything, they (we) are adding information. Its not widely known that edge angle has a large influence on cutting ability and edge retention. There are applications where modern CPM high wear alloys are not optimal. Those applications have been stated several times in other threads like this. Low edge angles, high polish, hard contacts or impacts, relatively strong materials (wood, plastic vs rope, skin, meat), and when a high sharpness is desired/required. Moderate to high edge angles, coarser finishes, relatively soft, abrasive materials, and tolerance for lower sharpness all favor modern high wear alloys.

That is exactly what they are doing, suppressing it... Going backwards.......

Instead of working to find ways to improve it, advancements in steels....

Taking what is there and building on that instead of tearing it down going backwards....

One would think they would be the ones at the top of the mountain shouting the loudest about the newer alloys and working to advance them even farther.

You would think anyway....

 

[me2]

One group is offering information that modern alloys are not optimal for all situations, which were outlined above. That same group is offering supporting research. The other group is essentially saying "You're doing it wrong for going outside what we think the parameters should be." The same group is also scoffing at contemporary research on the subject or essentially taking the stance that research only works in the lab by pushing "real world" testing. As for real world testing, I'd be interested to know if anyone has tried bone chopping with a CPM high wear alloy and had it come through without chipping on an edge less than 0.01" thick and 10-12 dps.

 

[Ankerson]

One group is offering information that modern alloys are not optimal for all situations, which were outlined above. That same group is offering supporting research. The other group is essentially saying "You're doing it wrong for going outside what we think the parameters should be." The same group is also scoffing at contemporary research on the subject or essentially taking the stance that research only works in the lab by pushing "real world" testing. As for real world testing, I'd be interested to know if anyone has tried bone chopping with a CPM high wear alloy and had it come through without chipping on an edge less than 0.01" thick and 10-12 dps.

That's defiantly something to look at.

I remember you said something about studying Metallurgy and that's great.

Hopefully if you want some day you may end up working in a real lab in that field, depending on what sub field you choose will depending on who for and in what Country.

Then you will understand what I ment.

 

[sodak]

Thicker angle than the edge of a splitting maul.



We? I don't thin my knives out nearly enough especially since giving away my wet grinder to a guy who could use it more and better, not having anywhere good to run my sander, and my D8XX is finally pooping out after 7 years of tendon-rending grindage.

So thicker angle then. I still don't understand what you mean. Most knives are both too thick and have too thick an edge angle for my liking. So are you saying that only knives with newer steels have edges that are too thick?

 

[sodak]

One group is offering information that modern alloys are not optimal for all situations, which were outlined above. That same group is offering supporting research. The other group is essentially saying "You're doing it wrong for going outside what we think the parameters should be." The same group is also scoffing at contemporary research on the subject or essentially taking the stance that research only works in the lab by pushing "real world" testing. As for real world testing, I'd be interested to know if anyone has tried bone chopping with a CPM high wear alloy and had it come through without chipping on an edge less than 0.01" thick and 10-12 dps.

Have we been reading the same thread? I see no supporting documentation and false outrage when any conclusions have been made, even when the scope of testing has been clearly defined - with no reasonable tests to prove otherwise. I've asked for testing data only to be met with silence.

It seems to me that those who prefer lower alloy steels feel as if their sacred cow is being slaughtered. I still refuse to choose one over the other. But I'll certainly smile more when using my CPM steels, knowing it's irritating a good many other people.

 

[Camber]

Have we been reading the same thread? I see no supporting documentation and false outrage when any conclusions have been made, even when the scope of testing has been clearly defined - with no reasonable tests to prove otherwise. I've asked for testing data only to be met with silence.

It seems to me that those who prefer lower alloy steels feel as if their sacred cow is being slaughtered. I still refuse to choose one over the other. But I'll certainly smile more when using my CPM steels, knowing it's irritating a good many other people.

What exactly happened to your D2 knife at 10 dps side? Could you please repeat that \?

Keeping in mind that D2 is a HCV steel, it might be interesting then to compare it to the quote I posted by Roman Landes, which is documentation considering who he is and what research he's done.

Oh never mind, I'll go ahead and do it.

From Sodak, post #196

I did a thread years ago playing around with a FFG D2 hunting knife. Took it way down to 10 DPS, (with a really thin grind) and had horrible chipping.

From Landes
"Landes measured the deformation of edges at the same edge cross section in response to microloading. He classifed steels into three groups, type I, type II, and type III mainly based on carbide volume, 0.5-5%, 5-15%, and greater than 15% respectively. These groups needed different angles to both take and hold a high polished sharpness, 8-12, 12-20, and 20-30 degrees per side respectively. The greater the size and volume of carbide, the greater the angle required to keep the edge stable. "

Would you please care to explain why it chipped then and how it doesn't illustrate the documentation from Landes's PHD thesis?

This is essentially one of the many questions I already asked in a previous post that was seemingly met in silence. Similarly, I asked if you noticed no difference between 10dps and 15dps on a thin edge, why not go 20dps or even 25dps to make it even more stable?

I believe I also made reference to the physics of rupturing and wedging (that's documentation which can be found in any textbook I'm sure) and how in many cases thicknesses behind the edge is irrelevant. I didn't notice any response to those comments though.

 

[Ankerson]

It seems to me that those who prefer lower alloy steels feel as if their sacred cow is being slaughtered. I still refuse to choose one over the other. But I'll certainly smile more when using my CPM steels, knowing it's irritating a good many other people.

That's called progress or advancements in technology.

While some seem to want to dwell in the past and that's fine and their choice to do so, but those types have always been around since the beginning of the human race.

Thankfully not everyone thinks the same way so hopefully we can keep moving forward as the years go on as new technologies come out.

So moving forward in a positive way is a good thing leaving the past behind and enjoying the newer technology as time moves on.

Or we can go back to the dark ages for a few thousand years again.......

 

[Camber]

Useless post...

 

[Camber]

Here's a few more questions that are logical extensions of the conclusions that "modern" is better.

Why did Phil Wilson stop using S125V?
Here's some documentation that can answer that question from Phils website:

CPM 125V is the best edge holding steel I have used to date. I have a small supply, maybe enough
to make about 20 blades. Crucible made one heat with this steel as sort of a test run and I was
able to get some of it to experiment with. The workability is very low in fact; I have had trouble
with a few blades cracking with the result of lost time and wasted abrasive. It has such a high
percentage of alloy that at optimum hardness (65/66) even with a very thin edge it is difficult to
sharpen. Given all of this, I have decided to drop it from my offerings of blade steel. I am hoping to
obtain some of the new CPM S110V to try out. It may take six months or more to obtain the steel,
get the heat treat right and do some field-testing. When I have confidence in my method, I may be
able to offer CPM S110V as a replacement for CPM S125V and as my higher end stainless blade
steel.

It would seem that modern can present problems as well, and not always be "better" despite it's edge holding.
The more important question might be why is it hard to sharpen? What makes it harder to sharpen over something like S110V? It could be the increased carbide load. I'd love to hear other thoughts though.

Along those same lines, why not advocate REX 121, Maxamet, T15? These would logically be better than S90V and S110V (if as I understand these represent a step up over S30V and CPM 154 which in turn represents a step over "old steels") since they include even more alloy and represent even more "technological advances".

 

[Ankerson]

Here's a few more questions that are logical extensions of the conclusions that "modern" is better.

Why did Phil Wilson stop using S125V?
Here's some documentation that can answer that question from Phils website:

It would seem that modern can present problems as well, and not always be "better" despite it's edge holding.
The more important question might be why is it hard to sharpen? What makes it harder to sharpen over something like S110V? It could be the increased carbide load. I'd love to hear other thoughts though.

Along those same lines, why not advocate REX 121, Maxamet, T15? These would logically be better than S90V and S110V (if as I understand these represent a step up over S30V and CPM 154 which in turn represents a step over "old steels") since they include even more alloy and represent even more "technological advances".

That's means take the current and figure out what is wrong and make it better, not everything is perfect.

Tearing it down and being negative isn't going to solve anything, take it and improve on it's faults.

Sitting around nitpicking about something on a forum and putting out walls of text about how this is this copied right out of some research paper or text book isn't going to accomplish anything other than driving people away and hurting progress.

The people on the forums aren't the ones who are doing the actual work in the labs at the steel companies or the knife companies etc.

Run the tests or whatever and send them to the Steel companies or the knife companies, they already know all about what is in those research papers and text books because that's what they do for a living... They are the ones that will make the difference though.....

All we can do is learn from the mistakes or the faults and find away to improve on those, that is what progress is.

That is what those smart people are supposed to be doing.

How many time did Thomas Edison fail before he got to were he needed to be?

He didn't give up....

So if one thing doesn't work, try something else, if that doesn't work try something else....

Progress doesn't mean going back 120 years and saying that works we will stick with that.

Nobody said it was easy, but that's what the people with the big brains do... Hopefully.

 

[shqxk]

Yeah, we don't due to production heat treating and the range they usually have to work in so it's understandable that they are kept in 58-61 range.

Unless the company can rent time in an aerospace furnace I don't see that changing anytime soon.

There is a very large difference in a Custom Knife Maker heat treating one or two blades at a time were every aspect of the process can be controlled and corrected on the spot and a production heat treater than runs 100 blades or more in a run.

Yes the K390 MT was in the 62-64 range, really more on the higher end of that 63-64 from the information that I have, but that's more rare and they did an excellent job with that one getting it to that high hardness.

Didn't know about that SY knife.

Final hardness of the steel has nothing to do with production or custom heat treat. Do you actually know how steel get hardenen?

When steel get heating to target temp then get soak for the right amount of time, the steel get quench in the proper media, that how we austenitizing steel and tranform it to the martensize, this actually how steel harden.

For some example 1095 which austenitizing at 1575F then quench in fast oil will have the as quenched hardness at about 66rc. If it were tempered at 390F the hardness will drop to about 60. Tempering at 250 and you will have 63-64rc 1095, the lower temering temp the higher final hardness.

Now do you see that the hardness of steel have nothing to do with the quality of heat treat. If some maker/company would like to get their HT to another level they can involve multiple normalizing/tempering or cryogenic, the method mentioned will help to reduce the grain/carbide size, reduce dislocation densities for forged blade and aid the distribution. HT in small batch also make it easier to control the temperature, and can run the HT process in even more precise time, nothing magic.

Then if a big company really have the full equipment with the right knowledge they can HT the blade at the quality no less than the best custom maker. I think you shoud stop overate custom HT since there still lot of custom maker who have only one paragon kiln and didn't care much about metallurgy.

 

[Gator97]

And something for the Science guys to chew on.

What if the Roman Empire either never fell or all of that Technology wasn't lost and or suppressed for over a thousand years.

Ironically enough... Stepanov, the father of C++ STD library (don't bother unless you're comp geek) had a speech at google and one of his main complaints about Romans was that they literally halted ALL scientific advance in all the places they conquered. Their philosophy was exactly that - "If it ain't broken don't fix it"... Yes, the bridges and sewer systemtn they've built 2K years ago still stand/work today but eventually it was one of the reasons of their downfall.

 

[Ankerson]

Final hardness of the steel has nothing to do with production or custom heat treat. Do you actually know how steel get hardenen?

When steel get heating to target temp then get soak for the right amount of time, the steel get quench in the proper media, that how we austenitizing steel and tranform it to the martensize, this actually how steel harden.

For some example 1095 which austenitizing at 1575F then quench in fast oil will have the as quenched hardness at about 66rc. If it were tempered at 390F the hardness will drop to about 60. Tempering at 250 and you will have 63-64rc 1095, the lower temering temp the higher final hardness.

Now do you see that the hardness of steel have nothing to do with the quality of heat treat. If some maker/company would like to get their HT to another level they can involve multiple normalizing/tempering or cryogenic, the method mentioned will help to reduce the grain/carbide size, reduce dislocation densities for forged blade and aid the distribution. HT in small batch also make it easier to control the temperature, and can run the HT process in even more precise time, nothing magic.

Then if a big company really have the full equipment with the right knowledge they can HT the blade at the quality no less than the best custom maker. I think you shoud stop overate custom HT since there still lot of custom maker who have only one paragon kiln and didn't care much about metallurgy.

Yes I already know that....

I can read the data sheets and have read some of the Books on the subject...

 

[Ankerson]

Ironically enough... Stepanov, the father of C++ STD library (don't bother unless you're comp geek) had a speech at google and one of his main complaints about Romans was that they literally halted ALL scientific advance in all the places they conquered. Their philosophy was exactly that - "If it ain't broken don't fix it"... Yes, the bridges and sewer systemtn they've built 2K years ago still stand/work today but eventually it was one of the reasons of their downfall.

Yes, in the places they conquered, but not in Rome proper.

And that was what was lost, they were very advanced for their time.

 

[me2]

Have we been reading the same thread? I see no supporting documentation and false outrage when any conclusions have been made, even when the scope of testing has been clearly defined - with no reasonable tests to prove otherwise. I've asked for testing data only to be met with silence.

It seems to me that those who prefer lower alloy steels feel as if their sacred cow is being slaughtered. I still refuse to choose one over the other. But I'll certainly smile more when using my CPM steels, knowing it's irritating a good many other people.

There's no outrage. At least not on my part. The documentation has been provided other places, as this discussion spans a couple of forums. New steels are great. They are made for a whole number of reasons. The latest steels in knives lean toward higher wear resistance. However, to say they are universally better is not the case. There are circumstances where they are not outperformed by the newer steels, as was my interpretation of the original post of the thread.

Not everyone uses knives with the kind of geometry considered typical. Very acute edge angles favor the higher edge stability steels. This acute angle has a large influence on cutting ability (ease of making a cut) and on edge holding (lower edge angles cut longer). Steels with lower wear resistance can handle lower edge angles. If someone doesn't use these lower angles, then the higher wear steels are for them. At least now everyone reading this thread knows and can check for themselves. Does a 15 dps edge on a S90V blade out last a 1095 blade at 7 dps? Maybe. It depends on what's being cut, the edge finish and the heat treatment. Will a 1095 or 52100 blade at 60-62 out last a S90V blade (same hardness) at 7 dps? Your experience with D2 indicates the S90V blade is likely to have issues, since it has even more carbides than D2. The 1095 or 52100 blade might, depending again on what's being cut and the finish and HT, but the low alloy steels have an advantage.

Ankerson, thanks for the vote of confidence. When I grow up, I wanna be just like you.

 

[thombrogan]

So thicker angle then. I still don't understand what you mean. Most knives are both too thick and have too thick an edge angle for my liking. So are you saying that only knives with newer steels have edges that are too thick?

I'm saying that steels with large carbides cannot hold polished edges with angles as thin as steels with small carbides. Where'd you get the other stuff?

But I'll certainly smile more when using my CPM steels, knowing it's irritating a good many other people.

You could accuse also people who aren't goo-gah about using certain types of steels for blade steels of trying to hold back scientific progress. I remember when I talked Jenny McCarthy into using a Frost's of Sweden mora and she started pretending the MMR vaccine gave her child autism the next day. Or that time I brought a knife made from 15N20 strip steel to parochial school and Intelligent Design started getting preached.

 

[Ankerson]

There's no outrage. At least not on my part. The documentation has been provided other places, as this discussion spans a couple of forums. New steels are great. They are made for a whole number of reasons. The latest steels in knives lean toward higher wear resistance. However, to say they are universally better is not the case. There are circumstances where they are not outperformed by the newer steels, as was my interpretation of the original post of the thread.

Not everyone uses knives with the kind of geometry considered typical. Very acute edge angles favor the higher edge stability steels. This acute angle has a large influence on cutting ability (ease of making a cut) and on edge holding (lower edge angles cut longer). Steels with lower wear resistance can handle lower edge angles. If someone doesn't use these lower angles, then the higher wear steels are for them. At least now everyone reading this thread knows and can check for themselves. Does a 15 dps edge on a S90V blade out last a 1095 blade at 7 dps? Maybe. It depends on what's being cut, the edge finish and the heat treatment. Will a 1095 or 52100 blade at 60-62 out last a S90V blade (same hardness) at 7 dps? Your experience with D2 indicates the S90V blade is likely to have issues, since it has even more carbides than D2. The 1095 or 52100 blade might, depending again on what's being cut and the finish and HT, but the low alloy steels have an advantage.

Ankerson, thanks for the vote of confidence. When I grow up, I wanna be just like you.

NO, be better than me, I missed my chance decades ago, it's your time now.

 

[james terrio]

This whole thread could just as easily have been named "Blade Geometry and Edge Angles-What's Wrong with Improvement?"

Well yeah... alloy selection and geometry do work together.

They can work against each other too... like the classic bad example of a high-alloy knife with a really thick edge. All that does is give you a knife that cuts poorly and is a huge pain to sharpen (more because of the thick edge than just the steel itself).

I agree, but except in some custom knives we don't see AEB-L and 52100 at high hardness, never even heard of 52100 over 60 being used.....

Latrobe's datasheet for 52100 claims as-quenched hardenability as high as 67Rc, so at least in theory fully tempered blades of 64 or 65Rc could be done. I'd have to ask my HT guy about that; maybe there's a technical reason we don't usually see them run that hard, even by custom makers.

I have made a lot of knives from O1 and will make more if that is what a customer wants, but I will always try to talk them into 3V because it is such a well rounded steel.

I completely agree. I like the way O1 cuts, but the thrill of sharpening knives wore off a long time ago for me. Many of my clients simply don't mind the fact that O1and 52100 don't stay sharp very long and they're easy to touch up... So, OK if that's what you want, great! My love affair with 3V is not because it's "super", but because it's well-balanced and versatile.

How many production knives in general do we see run above 60RC?

Not many, and I doubt we ever will. It's the problem of economy of scale working against the bigger manufacturers... grinding a whole boatload of 60+ Rc blades is awfully hard on machinery.

There are applications where modern CPM high wear alloys are not optimal. Those applications have been stated several times in other threads like this. Low edge angles, high polish, hard contacts or impacts, relatively strong materials (wood, plastic vs rope, skin, meat), and when a high sharpness is desired/required. Moderate to high edge angles, coarser finishes, relatively soft, abrasive materials, and tolerance for lower sharpness all favor modern high wear alloys.

If that's true, why aren't more (if any) competition cutters using O1 or 1085 in their blades anymore? Those cats have to perform both fine, controlled cuts and very aggressive cuts/chops in every run, without sharpening or stropping. By far the most commonly-used steel in competitions is CPM-M4 run hard, and those guys bring their edges down very, very thin and polish them highly.

What if the Roman Empire either never fell or all of that Technology wasn't lost and or suppressed for over a thousand years...

Meh... we just would have had massive pollution and nuclear weapons a thousand years sooner. We likely wouldn't even be here anymore.