[HN Gopher] CPM MagnaCut
___________________________________________________________________
CPM MagnaCut
Author : topsycatt
Score : 365 points
Date : 2021-12-26 20:42 UTC (1 days ago)
(HTM) web link (knifesteelnerds.com)
(TXT) w3m dump (knifesteelnerds.com)
| gxt wrote:
| Since I presume steel is a more or less uniform substance
| compared to biological processes, why is metallurgical research
| still more or less experiment first?
|
| Shouldn't it possible nowadays to bruteforce a search for an
| alloy of any given properties using computer simulations of the
| atomic or molecular structures?
| nutate wrote:
| Former computational materials scientist here. There are groups
| that are using ML for finding materials to simulate, and some
| beginning to use it to speed up simulations. Still that said,
| simulating cutting, abrasion, sharpening (I suppose it would be
| called to some extent tribology) is still in the infancy of
| simulation. Steel is extra difficult compared to other
| materials, and it has such a history of innovation that all
| exists at a sort of mesoscale out of reach of contemporary
| atomistic simulations. Still some have attempted it:
| https://www.dierk-raabe.com/icme/ or more recently:
| https://www.sciencedirect.com/science/article/abs/pii/S09270...
| Still the from Simulation/Search -> Experiment pipeline is
| working generally at much smaller scales that steel structures
| for now. ie micro instead of nano
| [deleted]
| Tuna-Fish wrote:
| The search space is much, much more vast than you'd imagine,
| and there are so many ways that things get non-linear that we
| have absolutely no idea how (way) more than 99.9999% of the
| possible alloys that we could make would actually perform in
| reality. The way most of the alloys we are using were found was
| that we started with something that we already knew, and then
| tweaked from there to optimize some property.
| kragen wrote:
| It's a good question; unusually, that doesn't mean I don't have
| a good answer.
|
| Steel is so far from being a more or less uniform substance
| that it's not even funny. There are four major phases that play
| roles even in the commonest carbon steel (ferrite, cementite,
| austenite, and martensite), plus others that can form at times
| like graphite, which plays an important role in cast irons.
| Ferrite and cementite can form nanolaminated microstructures
| called pearlite and bainite which have a major influence on the
| properties of the steel, and there are other microstructures
| that form depending on cooling speed, heat treatment, and cold
| working. So even the simplest steel is a nanostructured
| composite of metal and ceramic whose properties are hard to
| model computationally, though great strides have been made in
| recent decades.
|
| Then, once you add other alloying elements besides those two
| (intentionally or not), steel stops being so simple. You can
| find phase diagrams for most of the binary systems (vanadium-
| carbon, for example, or vanadium-iron) but most of the ternary
| systems probably include compounds that haven't been identified
| yet. In theory you could find them computationally, I think.
| Even when you have a phase diagram, though, that doesn't tell
| you how fast the phase transitions happen, which depends on
| things like the crystal structures of intermediate unstable
| phases.
|
| I don't know anything about this stuff, I just read about it.
| Recommended! Start with https://www.tf.uni-
| kiel.de/matwis/amat/generalinfo_en/guided...
| spekcular wrote:
| Naive question: Has anyone tried to whack these questions
| with the machine learning hammer? I figure if we can do
| protein folding [0], we should be able to do knives.
|
| [0] https://deepmind.com/blog/article/alphafold-a-solution-
| to-a-...
| chas wrote:
| Folks are certainly working on it from many dimensions, but
| it's a pretty hard problem since getting ground truth data
| involves making and testing materials, which is a very
| different problem to automate than training machine
| learning models. You need a fairly cross disciplinary team
| to make progress. As an example of folks doing good work:
| https://a3md.utoronto.ca/
| sseagull wrote:
| I don't believe we have a good way to compute various macro
| properties of something like steel. We can compute density
| and what not, but how much it holds its sharpness or
| something is something I haven't seen.
|
| So I am not sure how to get the training data needed for
| ML.
|
| (Computational chemist, but not computational materials
| scientist. So could be wrong!)
| mensetmanusman wrote:
| Kind of, deepmind actually recently published results in
| metal oxides:
|
| https://ai.googleblog.com/2021/10/finding-complex-metal-
| oxid...
|
| Steel has similar complexity since the number of
| combinations is so vast.
| saulrh wrote:
| That's still only, what, twenty or thirty dimensions? I guess
| it's hard enough to gather data that it's not as simple as
| feeding it a big black-box optimizer, something like
| SageMaker or Vizier that's designed to tune ML models with
| week-long training times and dozens of hyperparameters, but
| that'd still be quite a bit more powerful than the manual
| search that the author talks about.
| kortilla wrote:
| And do what? ML requires a way to know if it's making
| correct predictions.
| whatshisface wrote:
| Questions about prime numbers are asked in one dimension.
|
| The manual search is guided by a lot of very rigorous
| theory-of-experiment. It's not just trial and error, it's
| quite a bit more.
| notacoward wrote:
| AFAICT that is, to a large degree, what the author did. Much of
| the initial "exploration" seems to have been done in Thermo-
| Calc, with physical experiments following. IMO the novelty in
| _process_ is more exciting than the novelty of the result.
| colechristensen wrote:
| The important qualities of steel emerge out of microstructure:
| nanometer to millimeter sized features (several different
| crystal structures in the same material interacting through the
| boundaries between them and the bulk properties in them) which
| requires quantum interactions to be tracked through many orders
| of magnitude of scale. This includes how these different
| structures are formed though many stages of melting, tempering,
| work hardening, etc. In other words it is hideously
| computationally complex.
|
| One of many fields where yes there is a lot of simulation and
| yes it is developing but still quite far from having anything
| close to a complete model which can escape the need for
| extensive experimentation.
|
| There is a sort of prevalent idea among people outside these
| fields that simulations exist which can just handle anything.
| This is very wrong and quite far away.
| thesausageking wrote:
| There's a startup out of U of Toronto working on exactly this:
|
| https://www.thephaseshift.com/
| unbanned wrote:
| No. This is knives, not science.
| sfifs wrote:
| This is actually a great question and doesn't deserve to be
| downvoted. Indeed this is one of the considerations that led me
| to leave materials science research field after a couple of
| undergraduate projects with PhD candidates.
|
| It turns out that the domain between Angstroms (where we _can_
| computationally model atomic interactions accounting for
| quantum effects) and Milli (where standard Newton 's laws and
| therefore mechanical engineering tools can be used) is a vast
| computational desert.
|
| Most properties that affect bulk material properties happen to
| be developed in the micro-domain (note the photographs in the
| article) and almost 20 years after I've left the field, I don't
| believe there's still any rigorous "first-principles" based
| computational approach yet. In other words, materials are not
| uniform in the micro domain and this is where materials
| properties develop.
|
| So materials research process becomes hypothize, create
| material batch, test it 20 ways, rinse and repeat for a
| slightly different composition or process
|
| Even the software mentioned in the article (thermo-calc) is
| primarily empirical with some very smart extrapolations and
| modeling added (note the first step is experimental data
| capture [1]. It definitely is a massive step forward from when
| I was in the field but definitely not first principles based
| modeling.
|
| [1] https://thermocalc.com/about-us/methodology/the-calphad-
| meth...
| nqzero wrote:
| appreciate your use of "first principles based modeling". in
| my program, that's what we meant by "model based", but usage
| in the AI community is quite different
|
| your verbiage concisely captures what's so important about
| the concept
| kristjansson wrote:
| Per TFA, it is to an extent? The author briefly discusses a
| computational search of the design space, and uses that data to
| encourage the partner company to make a batch of the steel.
|
| That said, simulating material properties from atomic scale
| principles seems nontrivial compared to predicting them given
| observed parameters and properties of other alloys. I'd be
| interested in more informed comments on that possibility!
| bob_loblaw wrote:
| Very cool to see this pop up on Hacker News. I'm into pocket
| knives, and Larrin's new steel is generating a lot of hype among
| knife users and makers.
| insaneirish wrote:
| Larrin was on one of my favorite podcasts, Cooking Issues, to
| talk about various knife related things. Very good discussion.
|
| Episode link: https://www.patreon.com/posts/knives-out-
| with-52817284
|
| You do not need to be a Patron subscriber to listen to the
| episode. Also, if you're interested in the technical side of
| cooking and drink making, Cooking Issues is _the_ podcast to
| listen to. There 's a huge back catalog of shows on their former
| network, HRN, as well as a bunch of shows via their new
| arrangement.
| dunham wrote:
| Thanks. I occasionally read their blog back in the day, but
| didn't know they were still producing stuff.
| insaneirish wrote:
| And making stuff!:
| https://www.indiegogo.com/projects/searzall-pro#/
| MrMember wrote:
| Really interesting read. It's cool that a company like Crucible
| was willing to consider a proposal for something as expensive,
| time consuming, and potentially fruitless as a new steel from
| essentially someone off the street.
| aidenn0 wrote:
| He has a PhD Metallurgical Engineering and works in the steel
| industry (though on automotive steels, not on knife steels).
| Not quite the same as someone off the street. From TFA the
| company was mainly worried that his knife-steel knowledge was
| purely academic (since he's never worked professionally on high
| carbon knife steels).
| bob_loblaw wrote:
| Larrin's father is a famous custom knife maker who worked with
| making his own Damascus-style steel. Larrin, though his father,
| is well-known among the knife community.
| blacklion wrote:
| It is unfair to Larrin to attribute his success and well-
| knowness to the father.
| bob_loblaw wrote:
| I wasn't trying to do that so I should clarify. MagnaCut
| is, so far, a success because of his unique approach. I
| asked on another forum if MagnaCut is using some new
| process that makes the balance of properties so much better
| than other steels on the market. Most cutlery steel dates
| back decades. I thought maybe what MagnaCut is doing relies
| on technology that wasn't available back then. Larrin said
| no. He deserves credit for his fresh approach to making a
| cutlery steel, and I should not have implied otherwise.
|
| My poorly worded response was more to Crucible taking a
| chance on somebody off the street. Larrin is not some
| unknown quantity. He has connections in the knife industry,
| including Crucible. He's also a metallurgist with
| accomplishments in his own right. Crucible still took a
| risk, but it wasn't a huge one.
| bts327 wrote:
| Not really sure I'd call Larrin "someone off the street." They
| guy literally wrote the book on modern knife metallurgy and has
| a PhD in the science. https://www.amazon.com/Knife-Engineering-
| Steel-Treating-Geom...
|
| He also has a well known website and is considered one of the
| worlds leading experts on knife steels and knife craft.
| Straw wrote:
| How does this compare to Japanese steels such as HAP40 and Aogami
| White/Blue/Super?
| bob_loblaw wrote:
| If you look at White/Blue/Super funny they will rust. HAP40 is
| a high-speed tool steel. CPM M4 is a good comparison to it.
| MagnaCut will offer corrosion resistance that you don't tend to
| see in Japanese steels. MagnaCut will have better edge
| retention than White/Blue/Super. Those steels are low-alloy and
| rely on high hardness for wear resistance. MagnaCut has
| vanadium and niobium plus it can get pretty hard as well.
| MagnaCut is so far ahead of White/Blue/Super in this regard.
| Japanese steels are known for being great to sharpen (even
| HAP40). From what I have read, MagnaCut sharpens well.
|
| If we say that MagnaCut = stainless 4V and HAP40 = CPM M4, then
| HAP40 should have some more edge retention but less toughness
| when compared to MagnaCut. The differences aren't all that
| great. Corrosion resistance is the real difference maker.
| namibj wrote:
| Do you know how tungsten carbide with nickel binder stacks up
| in comparison? The usual cobalt binder of course isn't that
| good in terms of corrosion resistance, but for e.g. vegetable
| knife purposes, sharpness is very much required, toughness
| only so much as a brittle blade shatters if you look at it
| funny, and edge retention determines whether you have to
| (learn to) sharpen it at location, or can transport it to a
| service center.
| bob_loblaw wrote:
| It is hard to make comparisons like this. I know that is a
| crappy answer. But geometry by far the most important
| characteristic. How thick is the overall blade stock? How
| thick is the knife behind the edge? Those two things will
| matter more than steel composition. Then you have heat
| treat. A great steel with a crappy heat treat is going to
| make for a lackluster knife.
|
| But, regarding tungsten. There is a steel called Maxamet,
| and it is used in several knives by Spyderco. It should be
| noted that I am a Spyderco fanboy, so take my
| recommendation of this company with a grain of salt. I like
| them more than any other production knife company, perhaps
| to a fault. Anyways, Maxamet is run really hard, like 67
| HRC. Most production companies will run their knives in the
| upper 50's so the knives roll instead of chip. Quality
| production companies (Spyderco, Benchmade, Hinderer, Chris
| Reeve, etc.) will run most of their steels to around 59-60
| HRC. Maxamet can cut for a long, long time. This steel has
| 2.15% iron (which helps with attaining a higher hardness),
| 10% cobalt, 13% tungsten, and 6% vanadium. I can't think of
| another steel used in cutlery with as much tungsten as
| Maxamet. The cutting numbers from this steel are near the
| top of the charts. So Maxamet will blow MagnaCut out of the
| water when it comes to edge retention, but it was designed
| as a high speed tool steel. MagnaCut was designed to be a
| "jack of all trades, master of none". Steels like Maxamet
| require skill and some special tools as a sharpener. It's
| all about choosing the right steel for the job. Often
| tradeoffs are involved.
|
| Steel chart - https://www.spyderco.com/edge-u-cation/steel-
| chart/
|
| I will say that hard, thin knives have a reputation for
| chipping. Triple B Handmade Blades is a custom maker that
| focuses on maximizing cutting performance. So he uses high-
| carbide, high hardness, thin (like crazy thin) edges. You
| would think that his knives would shatter, but they do
| surprisingly well in his testing. Here's a short video of
| Rex 121 (has the highest percentage of carbide volume) heat
| treated to over 70 HRC. He is performing twisting cuts with
| a hard wood. At the end, the knife still cleanly cuts
| paper. You don't see/hear any chipping.
|
| https://www.youtube.com/watch?v=xAPMXGvrJ1I
| namibj wrote:
| Well, I was comparting to/with something like Durit's
| GD20N [0], which scores 1400 HV30 which should be like
| 83.6 HRC or thereabouts. It's a WC-Ni powder metallurgic
| composite with 9% binder. Their website suggests that
| they make blades for industrial paper cutters, but I'd
| assume those use normal WC-Co due to paper not being
| particularly corrosive.
|
| Sure, the geometry matters a lot, but that's also fairly
| orthogonal from the metallurgy.
|
| [0]: https://www.durit.com/en/technology/carbide#c1340
| nimbius wrote:
| I'm sure this will get down voted as its a Luddites call to arms,
| but all my cutlery is simple high carbon steel.
|
| Its cheap, holds an excellent edge, and in the kitchen it
| develops a wonderful rustic patina. For a pocket knife, a few
| drops of oil once or twice a year will keep it in good order, or
| you can chemically blue it if that suits your style as well.
| bob_loblaw wrote:
| The thing is, there's no such "best" steel. It all depends on
| what you want to do with the steel. I'm sure a custom maker
| will make a MagnaCut chef's knife, but I don't think you'll
| notice much of a difference. The corrosion resistance should be
| great, and that goes a long way with easy of maintenance,
| especially when cutting things like tomatoes. But most kitchen
| work is done on a cutting board (hopefully plastic or wood),
| and the material is quite soft. You can make a good argument
| that MagnaCut isn't needed in the kitchen.
|
| MagnaCut wasn't developed for the kitchen. Even though I am a
| self-professed "knife person" I just don't rely on a knife all
| that much where I would notice the difference between MagnaCut
| and VG10. So, on paper, MagnaCut is a big step forward compared
| to pretty much every steel. But that doesn't mean every steel
| is not obsolete. And, of course, we all have preferences. We
| like what we like, even if another option is "better" in some
| way.
|
| 52100 is a great steel. Sharpens like a dream. Sometimes,
| that's all that matters to a person.
| pas wrote:
| A (probably) completely different question: are there good
| knives for a kitchen that doesn't require maintenance? (So,
| are the ceramic knives any good?) I cook once in a blue moon,
| mostly pasta; so I'd use it mostly to cut cheese and
| sausages. Can you recommend a knife for this? (Or maybe it
| simply doesn't matter on such a small scale?)
| bob_loblaw wrote:
| When I think of maintenance, I think more about corrosion
| resistance. Is the knife 100% dry when I put it away? Do I
| want to take the time to wipe down the blade when I cut
| acidic food items? Then I think about sharpening. How long
| can I wait between sharpening? How long must I sharpen the
| knife? VG10 is a good knife steel for the kitchen. It is a
| Japanese stainless cutlery steel. You can find this steel
| on mass produced knives (Tojiro) and on many custom knives,
| which can be quite expensive. VG10 has good corrosion
| resistance, decent toughness, sharpens well, and can hold
| an edge a decent amount of time. An inexpensive combination
| King water stone is up to the task of sharpening VG10. It
| also does not take an inordinate amount of time to sharpen
| VG10. As a comparison, Magnacut will do everything VG10
| does but better.
|
| Another benefit of VG10 is that you often find it in knives
| from Japan. They understand that geometry cuts, so they
| tend to use thinner blade stock (but their knives are not
| brittle) and they tend to heat treat to 59-60 HRC. I think
| these knives are a good all-around package. Again, Tojiro
| is a good brand to start with.
| drran wrote:
| I have a self-sharpening stainless steel kitchen knife made
| in Czechoslovakia with waved edge. It never sharpened, but
| it still works just fine for everyday kitchen needs, except
| for peeling (I have a ceramic peeler for that), because of
| the waved edge. However, I have no idea where to buy a
| second one. <<Bread knifes>> with roughly similar edge are
| large, thick, and non-flexible.
| jacobian wrote:
| No, there aren't. Knives dull over time; even the most
| durable steel formulations need sharpening eventually.
| Those ceramic knives _are_ pretty robust, but they too will
| dull. More importantly, they 're extremely brittle; my
| experience with them is that they chip very quickly and are
| really unsuitable for anything other than very light use.
| For your use, they might be ok, but I think you'd end up
| being annoyed when they break sooner than you want.
|
| I recommend something from the Victorinox Fibrox line to
| folks like you who just want to cut stuff and not think
| about knifes. They're very sharp out of the box, quite
| durable, and will last a long long time before going dull.
| When they do, they're so cheap (like $25) that you could
| just get a new one rather than messing around with
| sharpening.
| TheSpiceIsLife wrote:
| Those $6 tools with the three grades of sharpening V's
| work well enough to make a $25 knife last fairly
| indefinitely in this particular use case.
| eeperson wrote:
| Although beware, those pull through sharpeners are
| notorious for doing a terrible job sharpening knives.
| They take off far more material than needed and tend to
| produce an edge that isn't very sharp. YMMV.
| TheSpiceIsLife wrote:
| I'm aware.
|
| The context here is someone who does little cooking and
| just wants a sharp knife three times a year.
| throwaway81523 wrote:
| I have a $5 rectangular chef knife that I got in Chinatown.
| I'm sure knife nerds would consider it crap, but it works
| fine. I have to sharpen it now and then. Dunno if that
| counts as maintenance. The simplest way to sharpen a knife
| is with a slack belt sander. I don't have one of those so I
| just sharpen it freehand on a cheap stone. No idea what I'd
| do with a fancy knife if I had one.
| namibj wrote:
| A remotely-decent stainless kitchen knife on non-fiberous
| materials will last long enough that you don't really have
| to worry about it. Especially for such soft materials as
| cheese and sausage.
|
| Vegetables are the problem for sharpness, and meat-with-
| bones the problem for toughness, assuming careful handling.
| So, yeah, with care to not bend it, a ceramic blade will do
| well on things like carrots, while a simpler stainless
| steel blade handles your cheese and sausages just fine.
|
| But even then, a very simple high carbon blade with a
| simple automatic-angle-keeping sharpening tool (10~20$)
| only needs to not see the dishwasher and receive oiling
| before storage. Which is basically the extend of "have an
| oiled sheath to store the blade in". French Opinel makes
| cheap (5~15 $) (but rather practical) pocket knifes out of
| (traditionally) such carbon steel. The wooden grip is more
| sensitive to water than the blade, in my experience.
| TheSpiceIsLife wrote:
| Any cheap or expensive knife that comes with one of those
| sheaves that have the sharpener built in will probably work
| well for your circumstances.
| jimmar wrote:
| I have family members who refuse to clean knifes properly. I
| need stainless steel. Personally, I'd prefer to have high
| carbon, but I know it'd be a rusted mess in a month.
| yumraj wrote:
| I've had great success with Victorinox stainless steel
| knives. They are pretty sharp, for us anyway, and seem to
| keep that way. And, they seem to be pretty reasonably priced.
| yumraj wrote:
| any recommended brands? or are these custom made?
| bob_loblaw wrote:
| Spyderco, but I am a fanboy. Their forums are really
| insightful. If you do down the rabbit hole of knives and
| steel, Spyderco does a better job of catering to this market.
| They experiment with all kinds of steel that will never make
| it to another production company. It should be noted,
| Spyderco knives tend to be on the "ugly" side. It took me a
| while to get them as a company.
|
| Benchmade, Hinderer, Chris Reeve, Spartan, Demko, etc. The
| list goes on and on. This is a great time to be a knife knut.
| yumraj wrote:
| > This is a great time to be a knife knut.
|
| Curious as to why is that?
| bob_loblaw wrote:
| Intricate knives requires high precision manufacturing.
| There are lots of small makers out there. Sharp By
| Design[1] is a one-man knife shop. He operates a CNC
| machine out of his garage in New Jersey. while his
| designs may not appeal to you, he puts a lot of time and
| effort into his knives.
|
| But his knives are expensive. He can only work so fast,
| and he has to charge a living wage for his time. Many
| people will scoff at paying several hundred dollars
| (perhaps over one thousand) on a knife.
|
| The rise in high-precision manufacturing in China means
| that Sharp By Design can partner with Reate (a well known
| Chinese knife manufacturer who does very good work) and
| offer his knives at a much more affordable price. He
| doesn't have to simplify his designs either. Other
| Chinese companies like We and Kizer are doing similar
| work. More and more custom knife makers are getting a
| deal with a company that allows their designs to be
| purchased by more and more people.
|
| Hell, there are people who are making a living as a
| designer partnering with Chinese manufacturing. They
| don't have the knife maker background. They have a good
| eye for design and understand the market.
|
| Thanks to Larrin and other prominent knife people, knife
| users have a better understanding of knife performance.
| We now know that geometry and hardness are important.
| Companies are slowly responding, Companies across the
| board are upping their game. Civivi (owned by We Knives)
| makes budget knives. Their quality, fit and finish, and
| steel choices are great for what you pay. You don't have
| to spend a lot to get a good knife. Everywhere you look,
| people and companies are getting better and better at
| making knives. Titanium used to be an exclusive material.
| Titanium frame lock knives are everywhere, and they have
| a price that is not prohibitive.
|
| Finally, Triple B Handmade Blades (Big Brown Bear on
| YouTube) is importing some of the highest quality diamond
| stones (not aluminum plates, but actual resin-bonded
| stones) available. They are very pricey (start at $350),
| but they allow you to easily sharpen high-hardness,
| carbide-packed steels.
|
| [1] https://www.sharpbydesign.com/
| [deleted]
| rkagerer wrote:
| This is a huge article. Can anyone give a 1-paragraph synopsis of
| its main thrust?
| TaylorAlexander wrote:
| new steel good
| RyJones wrote:
| The custom knife industry was really excited about SM100 at
| first, as well.
| dwohnitmok wrote:
| What happened to SM100?
| RyJones wrote:
| 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"
| bob_loblaw wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| Hmm, is vanadium carbide really harder than tungsten
| carbide, even at room temperature?
| bob_loblaw wrote:
| 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/
| kragen wrote:
| Interesting, thanks!
| spekcular wrote:
| 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.
| rdtwo wrote:
| Yeah I've bought a variety of tools over the years and
| all of them kind of suck. You need to be some sort of
| master craftsman with infinite time to use many of the
| sharpening techniques and tools or have already almost
| perfectly sharp knives.
| exhilaration wrote:
| You should Google your location + knife sharpening.
| There's probably a master craftsman within a few minutes
| drive of you that will sharpen your blades for a very
| reasonable price. There's a guy near me that will do
| small pocket knives for $2.50, prices go up from there.
| All of the local landscaping companies use him for their
| mower blades and chainsaws.
| rdtwo wrote:
| There is a fantastic place in Seattle that does it at 2$
| an inch or something. Just takes about a month
| mafm wrote:
| I'm not bob, but I bought a ruixin pro 8 (~40AUD) and 3
| diamond stones (~5AUD a piece) on aliexpress a couple of
| weeks ago.
|
| Watched a YouTube video and got half a dozen kitchen
| knives sharp enough to shave arm hair in about an hour.
| They seem to be holding their edges reasonably well a
| couple of weeks later.
|
| I'd previously not had much success with Japanese water
| stones and with the lansky(?) gadget.
|
| It seems like the key part of the process is (a)
| detecting when you have formed a burr so you know when to
| change sides/move to the next grit and (b) stropping at
| the end (get the leather strip with polishing wax).
|
| The Chinese gadget is a bit crude but was honestly
| surprisingly effective.
|
| I don't think the theory is that complicated but getting
| good practical results reliably can be a bit tricky. The
| gadget seems to work quite well for that.
|
| Ps: Just looked at Cliff Stamp's sharpening site. I think
| that's an order of magnitude sharper than I was going for
| with my kitchen knives.
| bob_loblaw wrote:
| Sorry, I stepped out to see the new Matrix film. I like
| the method of Murray Carter. He put out a DVD on blade
| sharpening, but has since released the entire thing on
| YouTube[1]. I have modified it a bit over time. I free-
| hand sharpen, but am not that great. You really only need
| a three-stone setup (coarse, medium, and fine) and a
| leather strop with diamond spray/paste. While diamonds or
| CBN are only really required for certain steels, I find
| diamonds to work wonders on a strop. You can get some
| quality stropping compound for cheap. I wouldn't worry
| about buying all of that at once though.
|
| There are so many different methods and tools you can
| use. I say find a well regarded technique and stick with
| it. Sharpening takes time. Sharpening can be distilled
| down to forming an apex and removing the burr. It doesn't
| matter if you use soaking stones, a fixed-angle
| sharpener, splash and go stones, sharpen with both hands,
| etc. You need to build muscle memory so there is as
| little change in angle as you sharpen. That will develop
| the apex. Then you need to remove the burr. You'll use
| different strokes, different pressure, and different
| tools. Focus more on the technique and worry less about
| the tools. Maybe Murray Carter doesn't appeal to you.
| Take a look at Big Brown Bear and Michael Christy (also
| on YouTube). Find a method that makes sense to you and
| practice a lot. Start with a simple technique with fewer
| grit jumps. You can add complexity over time.
|
| The best thing I got was a jeweler's loupe. You need to
| understand what you are doing (or not doing) at the apex
| to improve. Take your time and evaluate your work often.
| Even an inexpensive USB microscope is helpful.
|
| [1] https://www.youtube.com/watch?v=Yk3IcKUtp8U
| notacoward wrote:
| 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.
| thurn wrote:
| So is this getting us any closer to making a knife I can
| regularly put in the dishwasher, or are we still limited by the
| technology of our time?
| driverdan wrote:
| Why? It literally takes less than 15 seconds to clean and dry a
| stainless knife.
| teruakohatu wrote:
| I put my Victorinox in the dishwasher with no ill effect. The
| biggest danger is when a visitor decides to chop a tomoto on a
| ceramic plate.
|
| It's no Japanese chef knife, but a bargin for what it is.
| jerrysievert wrote:
| I have a nice set of Japanese chefs knives, and still use my
| victorinox on a regular basis. it's hard to argue with being
| able to drop it in the dishwasher.
|
| my 8" victorinox will be 8 years old in march, and is still
| going very strong, quite the bargain.
| bob_loblaw wrote:
| I read that Victorinox regular tests their knives with a
| dishwasher. While knife people will cringe at this, to many a
| knife is but a tool. When the tool is dirty, throw it in the
| dishwasher with the other dirty kitchen tools. Makes sense,
| but I'd never do it.
|
| The best part about the Victorinox line of knives is there
| handles. You can't ruin them with the dishwasher. Wood and
| other natural materials don't fare well in the dishwasher.
| Their steel (note quite sure what it is) is very corrosion
| resistant as well. It holds an edge long enough, and it is
| easy to sharpen. If you are a "knife is a tool" kind of a
| person, go with Victorinox.
| BatFastard wrote:
| Great looking knife, but 10 minutes of looking doesn't reveal
| where to buy one!
| scoopertrooper wrote:
| The post is more about the steel than the knife. The steel is
| quite new to market, so not many knife manufacturers have
| picked it up yet. However, here's one I found for you.
|
| https://www.knifecenter.com/item/SP41SYL5/spyderco-native-5-...
| bob_loblaw wrote:
| The first batch was given to smaller makers, often custom
| makers. Right now, Tactile Turn is offering a couple knives in
| MagnaCut (change the option in the drop down). I've seen people
| say they have used up their MagnaCut already. The steel will
| probably trickle into the market.
|
| Spyderco announced that the Native 5 Salt will come in
| MagnaCut. No date has been given for that.
|
| https://tactileknife.co/products/rockwall-thumbstud
| sillysaurusx wrote:
| Imagine spending $300 on a knife.
| BatFastard wrote:
| I can image spending 300 on a kitchen knife, not on a
| pocket knife.
| yial wrote:
| I have a flash II that I paid about $50 for.
|
| https://carbideprocessors.com/flash-ii-folding-knife-
| black-t...
|
| It's lasted me now 3 ish years, I carry and use it daily.
|
| I've gone through at least two cell phones in that time.
| (Three if I count a refurbished one that I shouldn't have
| purchased).
|
| If it's a tool that you use everyday... the daily use cost
| goes way down.
|
| I used to use Gerber Evos, and Evo JR. They were only about
| $20, but I could get maximum of a year out of them before
| they were falling apart and worn out. (Not to mention the
| pocket clip would often fail, and on a few occasions I
| snapped a blade..., once just trying to cut a small piece
| of pumpkin. )
| Camillo wrote:
| What do you do with a pocket knife every day? Whittle?
| sillysaurusx wrote:
| For real. I have a tiny swiss army knife that cost like
| $10. I use it to open packages, and I keep it in my
| pocket's pocket. (You know, the little flap thing that's
| in your right pocket for storing loose change or
| whatever.)
|
| Carrying around a knife that large seems miserable. I
| already wince when I wear pants that don't have a pocket-
| pocket (lol, I should probably find out the actual name).
| Carrying around a 4.5" knife is like ... why? Where do
| you keep it?
| banana_giraffe wrote:
| > I should probably find out the actual name
|
| It's called a "watch pocket", originally meant for,
| unsurprisingly, pocket watches.
| yial wrote:
| Carrying around a knife with a pocket clip... you won't
| even feel it's there. I also have a leather man wave + in
| the same pocket. I sometimes notice that.
|
| It's more comfortable in Jeans vs dress pants, but both
| work.
| remram wrote:
| Snap it to the back of your pants or your belt. Most
| knives have a clip.
| teslabox wrote:
| The little pocket on the right side of many pants is
| called the _watch pocket._ It was originally used to
| carry pocket watches. Because people don't commonly carry
| pocket watches anymore it's not as big as it used to be.
| jakear wrote:
| Coin pocket https://www.heddels.com/dictionary/coin-
| pocket/
| yial wrote:
| Open packages, cut boxes... various projects. Strip wires
| in a pinch. Improvised tool if one of the motorcycles I
| own from the 1980s breaks down.
|
| I do also commonly keep a leather man wave + in the same
| pocket.
|
| Other pocket tends to have car key, chapstick,
| streamlight, and a mala.
|
| Edit: I will say I've brought the flash II with me to at
| least 5 countries, and have used it to also once cut some
| chambira while on a boat on an offshoot off the Amazon
| river.
| vxNsr wrote:
| I take it you have a holster for your phone?
| robbedpeter wrote:
| Cardboard, cable, carpet, drywall, twine, plastic
| packaging and tape, letters, tags on pet toys, pillows, -
| a good knife made of a modern super steel can be a
| revelation. Get a good one and keep it handy, and you'll
| find situations daily where it genuinely makes life
| easier. For tech people, something like Leatherman
| skeletool is the ultimate every day carry because of the
| multi tool, and you can buy custom blades made from
| powder steel.
| causi wrote:
| Availability is hit or miss though. I've been trying to
| find an improved MUT blade for years.
| ChrisMarshallNY wrote:
| $300 is peanuts.
|
| Some of the high-end Japanese knives go for thousands.
| arwineap wrote:
| I was giddy over this article regarding the corrosion
| resistance. Was just eyeing a custom benchmade 20cv for a
| high saltwater exposure usecase; hoping this metal makes its
| way over there as well
| rdtwo wrote:
| That's a nice knife, the spiderco looks pretty shitty in
| comparison
| spekcular wrote:
| Spyderco takes pride in their knives looking ugly. They're
| totally form over function. Comparing the handles, I'm
| pretty sure the Spyderco would feel many times better in my
| hand. Also, they have amazing fit and finish, and come
| razor sharp from the factory.
|
| An expensive brand, to be sure, but I have only good things
| to say.
| rdtwo wrote:
| How do you sharpen those serrated blades? I get function
| on serrated but I don't really want a 150$ + knife to be
| disposable because it can't be sharpened
| spekcular wrote:
| It's tricky. Typically you get thin rods and do each
| serration individually. Spyderco sells their "Sharpmaker"
| for this. It's a bit overpriced; you can find decent
| substitutes elsewhere.
|
| Generally non-serrated edges are preferable unless you
| have a special requirement, like cutting rope. That
| yellow Native is part of their "salt" series for people
| who work on/around boats and water, and hence need to cut
| rope for sails, etc. Here corrosion resistance is
| obviously of paramount importance, which is why they use
| different steels for "salt" knives. There are also
| plainedge Natives around, for example:
| https://www.smkw.com/spyderco-native-5-lghtwt-blue-frn.
| [deleted]
| longitudinal93 wrote:
| Dawson Knives have numerous models:
|
| https://www.dawsonknives.com/collections/home-page
| [deleted]
| causality0 wrote:
| I wonder how MagnaCut compares to INFI. I've seen knives made of
| the latter do things I would've considered flatly impossible.
| bob_loblaw wrote:
| Elastic ceramic is a pretty wild material as well. You can do
| stuff with it that seems impossible with steel.
| The_rationalist wrote:
| Where can we buy magnacut knifes? (for cooking if possible)
| vxNsr wrote:
| This knife enthusiast[0] implies that this steel isn't
| necessary in the kitchen
|
| Though I had the same question, I'm guessing it'll be a few
| years and it'll be very expensive.
|
| [0]https://news.ycombinator.com/item?id=29697285
| bob_loblaw wrote:
| Spyderco already announced MagnaCut in their 2022 catalog.
| However, they are backed up at the moment. I am not holding my
| breath for a release in the near future. Custom makers tend to
| be on the cutting edge (no pun intended) when it comes to using
| "odd" steels. I expect more and more people to use it. That
| said, will Crucible make enough for demand? There's not a ton
| of money in knife steel production. Right now, Crucible's
| latest cutlery steel is S45Vn. S35Vn and S30V are still widely
| used as well. 20CV has taken off a bit too. I don't think
| Crucible will start making large batches just yet. But, I could
| be wrong.
| ks92 wrote:
| In metallurgy, several computational models are available based
| on specific applications. University of Cambridge is involved in
| neural network modeling. Just recently I published a paper that
| analyzed a welding electrode database to provide specific
| insights. One could see it here, https://s3.amazonaws.com/WJ-
| www.aws.org/supplement/2021.100....
| ChrisMarshallNY wrote:
| Now, _that_ is a labor of love!
|
| I find good chef's knives to be worth their price, but the truly
| _awesome_ ones are a bit out of my price /performance range.
|
| If I made my living as a chef, I might think differently.
| denton-scratch wrote:
| I like to cook; I bought a carbon-steel chef's knife 25 years
| ago, made by Richardson Steel of Sheffield. Regrettably they
| don't make steel in Sheffield any more, and that brand was sold
| to some Chinese company. The knife rusts if you let it; I call
| the result a 'patina'. It takes a wicked edge. It's still my
| go-to kitchen knife.
|
| Just now I'm a beardie-wierdie; but I usually shave through the
| summer, using straight razors. These are also carbon steel,
| although I think one of my razors at least must have some
| chromium in it - it seems to resist tarnishing.
|
| So: I wonder how this material compares to that Sheffield
| carbon steel for hardness and toughness. And I wonder how it
| compares with the Solingen steel my two daily razors are made
| of. As far as I'm concerned, a straight razor is the pinnacle
| of blade-making (I might take a different view if I was into
| swords).
|
| One of my razors belonged to my father, and is Sheffield carbon
| steel. It was made in the 1930s, and I can't get it nearly as
| sharp as the modern Solingen steel razors (I tried shaving with
| it once, but it wasn't 'smooth').
|
| I didn't get what hardening, tempering and annealing processes
| he applied; that makes a huge difference to the kind of steel
| you end up with.
|
| I'm just a blade user, not a metallurgist or cutler. I'm just
| interested in high-performance blades. I wonder if this metal
| makes nice razors?
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