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This is a huge article. Can anyone give a 1-paragraph synopsis of its main thrust?

bob_loblaw 5y ago
MagnaCut is the first knife steel that does the best job of balancing edge retention, toughness, and corrosion resistance. It is basically a stainless 4V (if that means anything to you). Larrin focused on reducing the amount or chromium needed. Lots of steels will dump chromium into the steel to help corrosion resistance. This only helps if chromium remains in solution and not forming carbides with the iron. Chromium carbides don't offer much in the way of wear resistance (unless you have a ton of them like in ZDP-189) and they are large carbides (relatively speaking) even after the particle metallurgy process. Basically, you give up toughness when helping corrosion resistance (ignoring steels with nitrogen). Larrin uses a lower amount of chromium than you would expect, but it remains in solution. So you get the stain resistance you want without the chromium carbides. Other benefits of the steel include grindability, which means makers can spend less time and abrasives on shaping the knife. You can obtain higher hardness than a standard stainless steel, which helps with forming an apex and removing the burr (sharpness for lack of a better word). Spyderco, a major player in the knife world, has a line of knives called their Salt series. These knives are supposed to be as rust-free as one can make. MagnaCut will first enter their catalog as a Salt knife. This was a big shock given how well LC200N (nitrogen-based steel used by NASA for ball bearings) can resist rust and remain tough (wear resistance isn't anything special though). Bottom line, Larrin built a well-balanced steel exclusively for knives. Many steels are adopted from other industries or were "knife-specific" but based on something like 440C, which was never intended for cutlery. So MagnaCut is upending the knife steel market by offering something you can't get elsewhere.
- jfengel 5y ago
  Is it possible to sharpen such a thing when it does get dull, or does that require a professional? In between sharpenings, does a steel work? (Sorry, I don't know much about steel or knife making. I just appreciate a really good kitchen knife.)
  - bob_loblaw 5y ago
    When we think of knife performance, it is the geometry of the blade that is the most important. I can give you a knife in MagnaCut with a thick edge. It won't cut for crap. So you want a nice, thin edge. Thin edges tend to roll/chip more easily. That is why you want a harder steel. So if MagnaCut is run hard, it will most likely dull before rolling or chipping. It will still cut, especially if you have think geometry. Once a blade starts to roll/chip, performance really suffers. That's when you need to sharpen. I have never sharpened MagnaCut, but it only has 4% vanadium (the hardest carbide) and 2% niobium (another hard carbide). You can probably get away with something like the Shapton Pro line of stones. They are readily available.
    - kragen 5y ago
      Hmm, is vanadium carbide really harder than tungsten carbide, even at room temperature?
      - bob_loblaw 5y ago
        All the research I have seen says vanadium is harder. That said, Sandrin Knives makes cutlery with a blade of nothing but tungsten carbide. This will outperform any steel easily. I have not seen a blade of nothing but vanadium. No idea if that is even possible. https://usa.sandrinknives.com/ https://usa.sandrinknives.com/
        kragen 5y ago
        Interesting, thanks!
    - spekcular 5y ago
      bob, what's your favorite resource(s) on learning to sharpen – both technique and theory (geometry, etc.)? I tried to get into the Cliff Stamp stuff, but it was really hard because everything was spread out across a zillion forum posts and YouTube videos.
notacoward 5y ago
Knife nerd comes up with an idea for how to make a steel with a novel combination of hardness / toughness, edge retention, and corrosion resistance. Persuades a real steel company to make a batch, which is tested eighteen ways from Friday by him, the company, and a bunch of knifemakers. Result turns out to be as good as predicted, maybe even a bit better. Bonus making it even more relevant to HN: most of the "discovery" was done via software, before any physical experiments (which are hard and expensive in this case). The fact that this new approach yielded good results is promising wrt developing steels with different properties.
TaylorAlexander 5y ago
new steel good
- RyJones 5y ago
  The custom knife industry was really excited about SM100 at first, as well.
  - dwohnitmok 5y ago
    What happened to SM100?
    - RyJones 5y ago
      Impossible to work with; the start up making it stopped making it. I’ve seen amazing knives made from it, but the knife makers I know that did said “never more”

MagnaCut is the first knife steel that does the best job of balancing edge retention, toughness, and corrosion resistance. It is basically a stainless 4V (if that means anything to you). Larrin focused on reducing the amount or chromium needed. Lots of steels will dump chromium into the steel to help corrosion resistance. This only helps if chromium remains in solution and not forming carbides with the iron. Chromium carbides don't offer much in the way of wear resistance (unless you have a ton of them like in ZDP-189) and they are large carbides (relatively speaking) even after the particle metallurgy process. Basically, you give up toughness when helping corrosion resistance (ignoring steels with nitrogen). Larrin uses a lower amount of chromium than you would expect, but it remains in solution. So you get the stain resistance you want without the chromium carbides. Other benefits of the steel include grindability, which means makers can spend less time and abrasives on shaping the knife. You can obtain higher hardness than a standard stainless steel, which helps with forming an apex and removing the burr (sharpness for lack of a better word). Spyderco, a major player in the knife world, has a line of knives called their Salt series. These knives are supposed to be as rust-free as one can make. MagnaCut will first enter their catalog as a Salt knife. This was a big shock given how well LC200N (nitrogen-based steel used by NASA for ball bearings) can resist rust and remain tough (wear resistance isn't anything special though). Bottom line, Larrin built a well-balanced steel exclusively for knives. Many steels are adopted from other industries or were "knife-specific" but based on something like 440C, which was never intended for cutlery. So MagnaCut is upending the knife steel market by offering something you can't get elsewhere.

jfengel 5y ago
Is it possible to sharpen such a thing when it does get dull, or does that require a professional? In between sharpenings, does a steel work? (Sorry, I don't know much about steel or knife making. I just appreciate a really good kitchen knife.)
- bob_loblaw 5y ago
  When we think of knife performance, it is the geometry of the blade that is the most important. I can give you a knife in MagnaCut with a thick edge. It won't cut for crap. So you want a nice, thin edge. Thin edges tend to roll/chip more easily. That is why you want a harder steel. So if MagnaCut is run hard, it will most likely dull before rolling or chipping. It will still cut, especially if you have think geometry. Once a blade starts to roll/chip, performance really suffers. That's when you need to sharpen. I have never sharpened MagnaCut, but it only has 4% vanadium (the hardest carbide) and 2% niobium (another hard carbide). You can probably get away with something like the Shapton Pro line of stones. They are readily available.
  - kragen 5y ago
    Hmm, is vanadium carbide really harder than tungsten carbide, even at room temperature?
    - bob_loblaw 5y ago
      All the research I have seen says vanadium is harder. That said, Sandrin Knives makes cutlery with a blade of nothing but tungsten carbide. This will outperform any steel easily. I have not seen a blade of nothing but vanadium. No idea if that is even possible. https://usa.sandrinknives.com/ https://usa.sandrinknives.com/
      - kragen 5y ago
        Interesting, thanks!
  - spekcular 5y ago
    bob, what's your favorite resource(s) on learning to sharpen – both technique and theory (geometry, etc.)? I tried to get into the Cliff Stamp stuff, but it was really hard because everything was spread out across a zillion forum posts and YouTube videos.

notacoward 5y ago

Knife nerd comes up with an idea for how to make a steel with a novel combination of hardness / toughness, edge retention, and corrosion resistance. Persuades a real steel company to make a batch, which is tested eighteen ways from Friday by him, the company, and a bunch of knifemakers. Result turns out to be as good as predicted, maybe even a bit better. Bonus making it even more relevant to HN: most of the "discovery" was done via software, before any physical experiments (which are hard and expensive in this case). The fact that this new approach yielded good results is promising wrt developing steels with different properties.

TaylorAlexander 5y ago

new steel good

RyJones 5y ago
The custom knife industry was really excited about SM100 at first, as well.
- dwohnitmok 5y ago
  What happened to SM100?
  - RyJones 5y ago
    Impossible to work with; the start up making it stopped making it. I’ve seen amazing knives made from it, but the knife makers I know that did said “never more”