Blade steels - what's wrong with improvement?

Another factor is urban legends and most of those are complete BS, but they die hard....

For instance, this chestnut:

Any steel, no matter what it is won't perform above it's alloy content all things being equal and assuming a proper heat treatment and made by someone who knows what they are doing.

The best Japanese style kitchen knives are made from Hitachi's white and blue paper steels and Swedish ingot carbon steels and they're made for some of the most precise cutting to appease some of the most discerning recipients of that food being cut (Kaiseki-style meals in Kyoto being the pinnacle). I don't know of any chef or itamae who's posted on a forum complaining it was time to brake out the Kitayama or J-nat because his or her knife just didn't have enough cobalt or vanadium to get the job done (though, to be fair, I only go to English language forums).

There aren't any magic heat treatments that will work miracles above and beyond what the alloy content of the steel is and anyone that says otherwise is fooling themselves because it just won't happen.

Agreed. That's why CPM-10V or CPM-S125V will be a perpetually bad choice for a yanagi or an outdoors chopper, but 1095 can make both without too much trouble (even though it'd be pushing it for 1095).

As an example 1095 will never outperform CPM 10V when cutting abrasive materials like cardboard or wild boar hide because the alloy content just isn't there.

Same goes for 420HC and CPM 110V, same as the last sentence, but in stainless.

Compared to the overall thickness of a blade, the finish of its edge, the angle of its edge, and even the hardness of the martensite, the steel type and alloy content is overblown. A thick knife made of S110V that's RC59-61 with a polished edge of 5 degrees per side will most emphatically not outcut a thin blade made of 1095 that RC65-66 with a polished edge of 5 degrees per side. Neither will a thin blade of S110V hardened to RC65-66 with a polished edge of 5 degrees per side. The S110V will lose that edge immediately and all the vanadium in the world won't do jack poopypants to help it.

And one can make scenarios and uses where the S110V will completely outshine 1095 such as scraping barnacles off fiberglass hulls.

But, as you say:

Another factor is urban legends and most of those are complete BS, but they die hard....
 
With regard to the disposable razor blades, I don't think the CPM etc steels will fit into how they are processed. They use very thin strip, rolled to the thickness, and kept under tension during forming. The higher carbide steels, even if they were better, probably couldn't stand the rolling or would play havoc with the dies used in forming.

Thank you for that me2. That makes a lot of sense. I hadn't considered it.
 
Can someone please post references to experiments demonstrating that an apex angle <30 inclusive is the way to go for razor-blades? Or are y'alll just talking about the primary bevel and not the actual apex geometry?

Verhoeven's survey of razor blade edge angles showed the apex angle to be between 7.5 and 9.5 degrees per side.

It also showed the recommended maximum angle for utility and kitchen knives to be 15 dps. as measured on several blades, and taking into account recommendations from sharpening references (Lee, Janitch, etc.) It also recommended a minimum angle of 15 dps for chopping knives. For the wood chopping/processing I do, I'm fairly confident I can go lower than that.

Keep in mind the edge stability research was concerned with the apex and back a very small distance. It doesn't consider the thickness behind the edge, just the very edge itself.
 
For instance, this chestnut:

Think of some local urban legends from around your area.

The best Japanese style kitchen knives are made from Hitachi's white and blue paper steels and Swedish ingot carbon steels and they're made for some of the most precise cutting to appease some of the most discerning recipients of that food being cut (Kaiseki-style meals in Kyoto being the pinnacle). I don't know of any chef or itamae who's posted on a forum complaining it was time to brake out the Kitayama or J-nat because his or her knife just didn't have enough cobalt or vanadium to get the job done (though, to be fair, I only go to English language forums).

Yeah we all know that and what the Japanese knives are made from, they don't use anything but Japanese steels in Japan.


Agreed. That's why CPM-10V or CPM-S125V will be a perpetually bad choice for a yanagi or an outdoors chopper, but 1095 can make both without too much trouble (even though it'd be pushing it for 1095).

Interesting


Compared to the overall thickness of a blade, the finish of its edge, the angle of its edge, and even the hardness of the martensite, the steel type and alloy content is overblown. A thick knife made of S110V that's RC59-61 with a polished edge of 5 degrees per side will most emphatically not outcut a thin blade made of 1095 that RC65-66 with a polished edge of 5 degrees per side. Neither will a thin blade of S110V hardened to RC65-66 with a polished edge of 5 degrees per side. The S110V will lose that edge immediately and all the vanadium in the world won't do jack poopypants to help it.

Edge and blade geometry is a huge factor in performance.


And one can make scenarios and uses where the S110V will completely outshine 1095 such as scraping barnacles off fiberglass hulls.

But, as you say:

Funny
 
One last question: What if the AEB-L and 52100 had been run harder (which is quite possible...AEB-L can reach 62-63, and so can 52100 as far as I know)....their edge stability would be even higher and so perhaps at those hardness 15dps wouldn't be necessary in Verhoeven's experiements. And in fact we often talk about the "super steels" having peak performance at above 60RC, so why limit the high edge stability steels the same way?

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.....

Compression strength increases as the hardness increases so yes you would be correct.

Would be interesting to see though, thin slicers around .005" behind the edge at higher HRC ranges.
 
How many production knives in general do we see run above 60RC? Spyderco's S90V and S110V are run at 59-61. I think the K390 got above that. I know there are others, but even many of the super steels are not being run at super high hardnesses in production.

And the Scrapyard Scrapivore is listed as 62-64 and is 52100.
 
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That's all well and good in theory. Edge-holding doesn't matter much if a person doesn't use the knife much, or only opens envelopes with it.

But serious knives are not typically used, or judged, in terms of weeks at a time. Let's take a hunter for example...

In practice, if a knife goes dull in 10 minutes instead of 20 or 60 or 120 minutes of field-dressing game animals... that's a pretty big deal.

Because it really only takes 10 minutes or so to clean out a deer or hog, and if my knife can't stay sharp that long, I'm gonna have some very angry phone calls/emails/forum posts to deal with. If my knife stays sharp for 2 or 3 or 4 deer/hogs/whatever (which might take several weeks or a year to actually get around to), I'm gonna have very happy people falling all over themselves to convince their friends to get a knife like theirs.

That is a good point that hasn't been discussed all that much in this thread.

Actual use of knives made by the Knife Makers and the fact that they have to perform in real use. :)

Also Actual use of the knives and that will vary from person to person as will the needs.


I absolutely agree. :thumbup: Geometry cuts, plain and simple. Thin is in. Alloy selection and HT should be matched to what needs to be cut, and how long the knife needs to keep cutting... and whether or not the knife is going to be subjected to a lot of impact ( big choppers, etc.)

Exactly. :)
 
How many production knives in general do we see run above 60RC? Spyderco's S90V and S110V are run at 59-61. I think the K390 got above that. I know there are others, but even many of the super steels are not being run at super high hardnesses in production.

And the Scrapyard Scrapivore is listed as 62-64 and is 52100.

I have thus far been able to avoid any Bussekin knives. This might just change my mind.
 
How many production knives in general do we see run above 60RC? Spyderco's S90V and S110V are run at 59-61. I think the K390 got above that. I know there are others, but even many of the super steels are not being run at super high hardnesses in production.

And the Scrapyard Scrapivore is listed as 62-64 and is 52100.

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. :)
 
Same books that everyone else reads or references, most of them have to be purchased or go to the library to read them.

Likely a whole section of them them in the library, I know there is in more than one I have been too.

Nothing new really.

For the benefit of those of us who don't want to sift through a section of the local library, are there any specific ones we should read?
 
Think of some local urban legends from around your area.

Most involve the utility of voting and supporting the Empire. Haven't heard anyone go on about diecutting steels and their suitability or lack thereof for knife blades.

Yeah we all know that and what the Japanese knives are made from, they don't use anything but Japanese steels in Japan.

i know not many people call you out on your statements about Cartech and Crucible alloy-chockalocka stuff, but I'll be the first to tell you Sweden; where Swedish steels are made; is not part of Japan.

Edge and blade geometry is a huge factor in performance.

Yep. That's why steels like the ones Cashmore cited are more appropriate for knives than knives incapable of supporting such edge geometries. Even though those steels are old, have that old steel smell, and lack sexified names.
 
Most involve the utility of voting and supporting the Empire. Haven't heard anyone go on about diecutting steels and their suitability or lack thereof for knife blades.



i know not many people call you out on your statements about Cartech and Crucible alloy-chockalocka stuff, but I'll be the first to tell you Sweden; where Swedish steels are made; is not part of Japan.



Yep. That's why steels like the ones Cashmore cited are more appropriate for knives than knives incapable of supporting such edge geometries. Even though those steels are old, have that old steel smell, and lack sexified names.


Haven seen any Japanese made knives that use steels that aren't produced in Japan.. ;)

What edge and blade geometries would those be?
 
Misono has a Sweden Steel series; Aoki Hamono uses AEB-L; Suisin uses 19C27; Japanese Chefs Knife in Seki OEMs a Swedish Stainless house brand; and Sakai Ichimonji, Ichimonji Chuko, Ginga, and Sakai Yusuke all offer Swedish steel knives as well.

Not that I'm obsessed with Japanese made knives with steel appropriate for acute edges or anything...
 
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