Sharpmaker enough for M4 or K390?

[MFlovejp]

You can maintain K390 and M4 just fine on a Sharpmaker. K390 is not known for being prone to chipping- in fact I’ve seen Shawn from BBB do some impressive things with it, such as batoning through coins without damage.

If you need a steel that can cut carpet and cardboard and scrape labels off glass I think you’ll find most of Spyderco’s offerings up to the task. you might stay away from Magnacut, S110V and the like just to avoid potential chips. They do make a Native 5 Salt in Magnacut if that’s what you’d like to try.

Try not to do too much “eyeball chemistry” with the data from Knife Steels Nerds- there’s a lot more to it than “a pinch of this adds toughness,” etc. Larrin is frequently on these forums if you have questions for him.

The Centofante is a beautiful knife- I carry mine on dressy occasions- it may not be ideal for the harder use you describe due to the small slick handle but VG10 itself can certainly handle the use you describe.

There is a lot of information out there. A lot of that information is based purely on someone’s personal opinion. I urge you to try different things and form your own opinions through testing on what your needs and uses are.

Welcome to the forum!

[Cl1ff]

Today I took my CPM-15V Manix 2 out and dulled what was left of the edge on some cardboard and copper staples. The edge got some minor deformation and blunting. Not enough to hinder the cardboard cutting much, though.
Usually I'd go for the CBN plate, but for the sake of this thread I brought out the Sharpmaker.
I was able to sharpen out the damage in a few minutes of concentrated strokes on the CBN rods. A section of blunting just took a little bit to bring up a bur on. Otherwise the rest of the edge had a burr super quick. Did that for both side and then removed the bur. At that point I had rid the edge of any deformation and it was slicing paper and decently shaving despite the rough edge from low grit CBN. Honestly, I'm still building skill and my sharpening is not without error, so I can definitely still improve my edges right off the CBN.

I decided to refine the edge on the brown ceramic rods. This is a little trickier for me because its hard to detect the bur and I want the smallest bur I can with the least amount of strokes to maintain some of that aggression from the lower grit I like. However, it is still pretty easy and i got it to noticeably shave hair and slice paper better. The new 15V edge is about as sharp as any of my edges, honestly one of my better ones, and it took just a few minutes on the Sharpmaker.

[dan31]

Thank you for the effort to run 15V through the Sharpmaker progression. It’s all about getting a good result from the CBN/diamond first step. Just like using stones freehand. You have to get the apex set on the first low grit step, then refine.

[kennethsime]

I'm pretty sure the people here who are "more skillful and knowledgeable" have never depended on just a Sharpmaker, so I'm really depending on novices who have used Sharpmaker on M4, K390, and other tool steels with 4% or higher Vanadium.

FWIW, I have a guided system (the worksharp precision adjust) and mangled a few of my knives with it. I’ve also done a few good jobs with it. You’ve got to get the clamping down, and the practice (like any other skill) or you can get some really uneven bevels.

Since I got my CBN rods, I haven’t bothered using the worksharp to work on my Spydies. The Sharpmaker has a 15dps (15°) and a 20dps (40°) setting and honestly that’s enough for me.

I do still use the Worksharp for bigger knives, but I think that a Gauntlet or Galley may be in my future. The croc stick method is just more idiot proof for me.

[bleasure]

Want to answer directly to m4 in a hard use folder, the Gayle Bradley 2 is hard to beat. I’m sure it can handle anything you throw at it.

2nd'd

My gb2's m4 is insanely good. I just gave it the tiniest touchup on the sharpmaker, like 4 or 5 passes max on the grey rods for the first time since getting it in november and using it almost daily, and it's so sharp it cut into my fingers while i was feeling the edge. I was doing so the same way I have five million times before, with every knife i've ever owned - very light, careful touch feeling for edge quality and burrs. That's never happened before. Didn't draw blood, but it startled me, and then left me extremely pleased.

You also simply can not go wrong with cruwear. Significantly tougher, a breeze to sharpen, essentially stainless, and holds an edge really well. It's one of the top 2 or 3 all-rounder steels you can get

[MFlovejp]

You can maintain K390 and M4 just fine on a Sharpmaker. K390 is not known for being prone to chipping- in fact I’ve seen Shawn from BBB do some impressive things with it, such as batoning through coins without damage.

If you need a steel that can cut carpet and cardboard and scrape labels off glass I think you’ll find most of Spyderco’s offerings up to the task. you might stay away from Maxamet*, S110V and the like just to avoid potential chips. They do make a Native 5 Salt in Magnacut if that’s what you’d like to try.

Try not to do too much “eyeball chemistry” with the data from Knife Steels Nerds- there’s a lot more to it than “a pinch of this adds toughness,” etc. Larrin is frequently on these forums if you have questions for him.

The Centofante is a beautiful knife- I carry mine on dressy occasions- it may not be ideal for the harder use you describe due to the small slick handle but VG10 itself can certainly handle the use you describe.

There is a lot of information out there. A lot of that information is based purely on someone’s personal opinion. I urge you to try different things and form your own opinions through testing on what your needs and uses are.

Welcome to the forum!

[DunninLA]

thanks for all the input. I've decided that for this knife, for the purposes of utility work around the house, some poking, prying, some scraping, some light chiseling ... don't need a wear resistant slicing machine. Just a very small knife that is tough. So K390 is out. Seems like some other tough steels that might work are really uncommon, so I don't think I'd easily find a very small knife in those steels... 14c28N, and 3V.

Also decided I want a very small knife for this purpose.

I'm down to 5 steels generally available -- Cruwear, Nitro V, M4, Magnacut or LC200N. I have no doubt at this point that none of them would be too difficult to maintain on the Sharpmaker, especially since I already have the diamond rods in the case of M4 repair.

I would have already bought today the Civivi Baby Banter in Nitro V, but its handle truly does not 4 finger gripping in that the choil doesn't really work effectively (or safely) for the index finger... saw one reviewer nick himself trying to use the choil. So Nitro V is probably out since nobody else makes a very small knife with it.

Now I'm down to waiting on a used Lil Native in M4. Don't want to spend much more than $100.
Seems to be the only really small, usable four finger grip knife of high quality is Lil Native, and it doesn't come in Nitro V, Magnacut, Cruwear or LC200N. I would consider Poliwog in M4 also, but they seem to be pretty expensive new and I havent' seen any used ones come up lately.

This exercise has been fun... deciding exactly what I want a knife to do in real life, and finding the best fit for that use.

[JSumm]

May want to look at the Native 5 in SPY27. I use mine specifically when I need a beater around the house working on projects. Smaller blade than I EDC, but I like the control. And honestly the Native 5 is pretty thick. I never felt like I was going to break the blade. SPY27 seems to be run fairly hard. The edge holds up very well and sharpens up nicely. Especially on the Sharpmaker.

[shunsui]

The key to the sharpmaker is the diamond rods. I can't believe I went so long without them.

[DunninLA]

update. I don't think I will find anything size of Lil Native in any of those tougher than average steels... Cruwear, Magnacut or M4.

So, I'm now back to settling for an approx 3" blade, and that gives me two current options... 1) Magnacut in Native 5 Salt PE at $152, which I'm assuming will be out in the next few weeks, and 2) Cruwear in Endela at DTC exclusive at $109. I don't need the stainless-ness of the Magnacut, being in Socal and using it around the house, but that guy in AUS keeps cutting his saisal rope and Magnacut is biting at the heels of k390 for edge retention, far ahead of M4, which is a little ahead of Cruwear, all using Mules, plus a few other data points.

At this point M4 is out, since I can have better toughness, and better corrosion resistance with Cruwear or Magnacut, and with Cruwear, almost the edge retention, and with Magnacut, much better edge retention. Doesn't seem like there's any reason for M4 anymore.

I prefer the form factor of Native 5 over Endela, and seeing that Magnacut is almost as tough as Cruwear, and much, much better edge retention, I think I'll just spend the extra $40 and wait for the Native 5 Salt Magnacut PE. It's looking like LIl Native in Magnacut would be my perfect fit, since it isn't available, Native 5 will have to do.

[Cl1ff]

I think you'll be happy with a MagnaCut Native 5.

This is just some food for thought, not me trying to change your mind.
The video below demonstrates edge strength and stability pretty well. Spyderco tends to run rex45 a bit harder than M4, so despite being very similar steels, the harder edge resists deformation better. The whole blade won't be as tough, though.
You just have to know which behavior is better for you. I think that, if you pry with the tip, you will inevitably break it off, regardless of steel. Thicker edge geometry will be tougher and I suggest, actually I know, a saber ground Spyderco is better for that.

https://youtu.be/WOpu13O_OFE

Here's another interesting post to consider (the pictures make it seem longer than it is). It happens to be about Rex45 as well, but I'm including these more so because I think its relevant to a discussion like this about steels in general, especially when considering what characteristics are actually desirable for you.

Two years ago I was curious what would happen if I gifted a brand new Spyderco Military model in CPM REX 45, 8% carbide volume, 67.0 HRC and low fracture toughness to a "non knife geek" heavy knife user. This knife has been put through **** it was even left outside in the rain for 2 weeks.



He was an interesting test subject to explore this question because never in his life has he spent more than $50 on a pocket knife and does not care about blade steel so their was no bias from him.




His most used knives were Buck 420HC, I met him when I was a professional knife sharpener and his knives would blunt completely smooth very quickly so I could see objectively his knives were being heavily used and why he checked all the boxes for an excellent candidate to further explore a curiosity.




Well, the knife was put through complete ****, I was surprised it was in one piece, the g10 peel ply is worn smooth so I got a lot of time in the hand from the end user. What was most shocking was that the edge retention was subjectively and objectively better than softer, tougher steels he had experienced.



Without asking leading questions he explicitly stated,

"Yeah that's the best knife I've ever had, just keeps cutting"





He was genuinely stoked about the performance.






Most knives in his use blunted to +1000g on the BESS tester, the softer tougher steels had little resistance to deformity and the edge would smash down in use quickly, I was surprised to see the edge under 500g Bess after the first YEAR.



This knife was only sharpened once when I met him again at Shot Show 2022 in Las Vegas at the Spyderco booth, it was sharpened to 200g BESS with the Spyderco sharpmaker using the diamond rods and finished on the white ceramic.



Its been almost a whole year since it was sharpened and it was nicely maintaining a sub 500g BESS edge with heavy use. NOT +1000g BESS with other steels I've seen from him, so there is real world evidence that the increased cutting edge retention seen in controlled testing does cross over to the reality, the problem is that these steels are expensive and difficult to process, heat treat, and you can't use Grandpa's arkansas stones.





Edge tested 1" from heel


Edge tested 1" from tip




Translation of BESS to paper cutting sharpness








In his perception, if the knife is still physically cutting it is still sharp. What the Rex 45 did was it did not blunt completely smooth at the edge and it could still physically cut without extreme force and slipping compared to a "tougher" softer steel that would have blunted smooth with lots of physical cutting.







The biggest take away I feel for readers is that one should give things a try first hand and see if it works or doesn't work for their preferences and uses.







I'm pretty sure the CPM REX 45s low toughness would be better seen if we duct taped it to a poll and tried to cut a concrete wall in half, but there are probably better and cheaper tools for demolition work.

Again, it may seem like I have a thing for Rex45, but it is just a coincidence that a Rex45 Native 5 from GPknives is, I think, the least expensive Native 5 available for $112. It might be a good option if you're wanting to save some money.
https://www.gpknives.com/spyderco-nativ ... 1pwh5.html

[Ryder]

I’ve done a complete reprofile on k390 with 400 grit sandpaper. It takes a bit longer than some softer steels but it came out amazingly well. I’ve had and used a Sharpmaker for 20 years now and you can absolutely use that. Again it will take longer but with patience it will work. I’ve never tried the diamond rods yet but sounds like they do it faster.

I’m finding the convex edge on k390 is very durable and freaking sharp.

[bleasure]

update. I don't think I will find anything size of Lil Native in any of those tougher than average steels... Cruwear, Magnacut or M4.

So, I'm now back to settling for an approx 3" blade, and that gives me two current options... 1) Magnacut in Native 5 Salt PE at $152, which I'm assuming will be out in the next few weeks, and 2) Cruwear in Endela at DTC exclusive at $109. I don't need the stainless-ness of the Magnacut, being in Socal and using it around the house, but that guy in AUS keeps cutting his saisal rope and Magnacut is biting at the heels of S90V for edge retention, far ahead of M4, which is far ahead of Cruwear, all using Mules.

At this point M4 is out, since I can have better toughness, and better corrosion resistance with Cruwear or Magnacut, and with Cruwear, almost the edge retention, and with Magnacut, much better edge retention. Doesn't seem like there's any reason for M4 anymore.

Magnacut doesn't have near the edge retention M4 has as far as I've seen, on any consistent basis. I'm ready to be proven wrong, but one massive outlier test result by Cedric and Ada doesn't compare with years of competitions and plenty of CATRA tests generally showing otherwise, it seems to me. Cruwear too has on average, depending on everything, just as good edge retention as Magnacut and potentially greater toughness. Magnacut's genuinely freakish advance, it seems to me, is its stainlessness in relation to those other two categories being very good.

fwiw, this lil native in cruwear came out recently, it's probably the most attractive one out there for my money. I expect it wouldn't be hard to find used on, say, reddit, given how long it took to sell out: https://www.theknifejoker.com/product/s ... lain-edge/

[DunninLA]

update. that guy in AUS keeps cutting his saisal rope and Magnacut is biting at the heels of S90V for edge retention, far ahead of M4, which is far ahead of Cruwear, all using Mules.

At this point M4 is out, since I can have better toughness, and better corrosion resistance with Cruwear or Magnacut, and with Cruwear, almost the edge retention, and with Magnacut, much better edge retention. Doesn't seem like there's any reason for M4 anymore.

Magnacut doesn't have near the edge retention M4 has as far as I've seen, on any consistent basis. I'm ready to be proven wrong, but one massive outlier test result by Cedric and Ada doesn't compare with years of competitions and plenty of CATRA tests generally showing otherwise, it seems to me. Cruwear too has on average, depending on everything, just as good edge retention as Magnacut and potentially greater toughness. Magnacut's genuinely freakish advance, it seems to me, is its stainlessness in relation to those other two categories being very good.

. That's what I thought too.

But if you take close to edge retention of k390, and almost the toughness of Cruwear, and close to the corrosion resistance of LC200N or Vanax, well, that's a friggin miracle steel.

It wasn't one edge retention test. First off, using Mules is the absolute best test conditions one could hope for. Heat treat is probably close to maximized and blade geometry is the same for all.
He's also had a second test just recently... Here it is --https://youtu.be/bvPdb-n3__Q&t=327s

This vid was a test of how many more cuts than about 1000 could a Mule Magnacut get with a dual grit sharpening technique he had heard about.... mirror one side, toothy other side. And he got 1550 sisal rope cuts, while still slicing paper without getting hung up ... from a Magnacut Mule.`

I remind you, in his Mule test, k390 got close to 1000, as did MagnaCut, M4 600-640 and Cruwear about 450-500.

So that's two data points, two vids, and his methods are sound. He has done I think three vids with Magnacut Muler. Maybe Magnacut likes Sisal rope more than any other medium (CATRA, Cardboard). Maybe the sisal rope vendor put out fake sisal rope. Maybe Magnacut mysteriously reorganizes its molecular structure in the southern hemisphere, where water circles down the drain backwards. Either that AUS guy is purposely misreporting, has taken leave of his senses, which I find next to impossible, or Magnacut is more than even Larrin has been saying. Larrin has Magnacut behind M4 in edge retention, equal with Cruwear in his tables.

No wonder Larrin pushed back on calling it Larrinite... he's been hugely sandbagging the whole time... sitting on a metalurgical gold mine and didn't wan't to let it all out at once... but now the r eal world data is coming in.

If you want to disregard those two/three sisal rope cutting results he got with Magnacut using the Sypderco Mule at 17 degrees, one with mirror polish edge, one with dual grit sharpening, then you're going to have to show where his methodology was faulty. You're also going to have to esplain why Larrin in a way endorses his methodologies in a general sense by linking to them in his CATRA relevance article. I'm open to suggestions, b/c this is just strange that Magnacut is retaining an edge so long. On the other hand, the notyouraverageEDC girl reported rolling the edge of Hogue Magnacut she was lent with her finger. And I KNOW she calls it like it is without any regard to repurcussions.

My best guess is that if you hit the heat treat exactly right, and then don't ruin it on the grinding wheels, it seems Spyderco did for the mule, that Magnacut has incredible performance in the field.

[bleasure]

update. that guy in AUS keeps cutting his saisal rope and Magnacut is biting at the heels of S90V for edge retention, far ahead of M4, which is far ahead of Cruwear, all using Mules.

Magnacut's genuinely freakish advance, it seems to me, is its stainlessness in relation to those other two categories being very good.

If you want to disregard those two/three sisal rope cutting results he got with Magnacut using the Sypderco Mule at 17 degrees, one with mirror polish edge, one with dual grit sharpening, then you're going to have to show where his methodology was faulty. You're also going to have to esplain why Larrin in a way endorses his methodologies in a general sense by linking to them in his CATRA relevance article. I'm open to suggestions, b/c this is just strange that Magnacut is retaining an edge so long. On the other hand, the notyouraverageEDC girl reported rolling the edge of Hogue Magnacut she was lent with her finger. And I KNOW she calls it like it is without any regard to repurcussions.

I take your points well, and as I say, if people over time really start to replicate that experience it'd be amazing and I'm very prepared to be convinced. As it stands, I don't think it's reasonable to say magnacut is equivalent to k390 when there's almost no evidence to suggest this by any meaningful standard, including the tests of the steels' own formulator. I think you might really be on to something when it comes to the medium of C&A's tests though, it may be that MC is particularly excellent at dealing with those kinds of media! There's also the basic reality that edge holding and cutting ability have, idk, 10x more to do with angle/edge than with steel, though obviously different steels like and respond differently to different edges

I had the video you linked in mind. I was surprised by those results as C&A appeared to be, and there's no question: they happened. But I'm basing my estimation of magnacut on A.) my own magnacut mule's performance, B.) Larrin Thomas' own CATRA tests and accounts of the steel he personally co-developed and tested in the most controlled way I've seen presented so far, C.) iirc the interesting but not super generalizable results BBB(?) got testing it alongside some others, including a cru-wear knife that 'outperformed' it (so to speak), and D.) the long-standing and massive opportunities folks have had to use m4 at a pretty wide array of heat treats, situations, angles, etc. I can't think of a thing to complain about with MC, which is the most remarkable thing about it in a way - it just doesn't suck at anything, and appears to be (relatively speaking, depending on use case) set up to be good to great at pretty much everything.

My own direct experience with MC is underwhelming, but again, even if it's a lot more 'data points' so to speak, it's a single person with a single knife and not much can be extrapolated. For a 5 month period, I used nothing but my mule for food prep while relocated for a job. Nobody in their right mind would suggest a mule is an ideal kitchen knife, so, all qualifiers and grains of salt included. But my mule chipped quickly and often despite being used on soft objects and wooden/plastic boards exclusively, and honestly, dulled surprisingly quickly [inb4 'factory edges,' which is truly a fake idea, and irrelevant anyway due to resharpening]. I compare this experience with a generic stainless 6" kitchen knife with similarly thick geometry (for kitchen uses), which performed roughly equally in terms of efficacy, dulling, and chips.

So again, I'm ready to discover it really is all that you appear to hope it is, but until there's more evidence across the board, all of the above & more suggest to me, at least, that there's a lot of hyperbole. I expect the reality to be a little more modest, if still by comparison kind of amazing, and I'm still prepared for something genuinely gold to emerge from all the glitter. Lemmy knows I wouldn't blink at snagging an *actual* kitchen knife in MC to try, despite my experience.

[Wartstein]

Just the quick 2c of an anything else than master sharpener (aka ME ):

As far as I know Spyderco runs REX45 noticable harder than M4, still I have no problems sharpening it on the Sharpmaker. My CBN rods make the process a lot quicker of course.

[apollo]

The key to the sharpmaker is the diamond rods. I can't believe I went so long without them.

That is if they even fit you’re sharpmaker base… have 2 of them can only use 1 and that one doesn’t even fit like it should its a pain to get in and an even bigger pain to get out of the base.
Plus for some reason mine do not seem to be cutting the steel aggressive enough in comparison to my new worksharp precision adjust its diamonds.

[The Home Slice]

update. that guy in AUS keeps cutting his saisal rope and Magnacut is biting at the heels of S90V for edge retention, far ahead of M4, which is far ahead of Cruwear, all using Mules.

Magnacut's genuinely freakish advance, it seems to me, is its stainlessness in relation to those other two categories being very good.

If you want to disregard those two/three sisal rope cutting results he got with Magnacut using the Sypderco Mule at 17 degrees, one with mirror polish edge, one with dual grit sharpening, then you're going to have to show where his methodology was faulty. You're also going to have to esplain why Larrin in a way endorses his methodologies in a general sense by linking to them in his CATRA relevance article. I'm open to suggestions, b/c this is just strange that Magnacut is retaining an edge so long. On the other hand, the notyouraverageEDC girl reported rolling the edge of Hogue Magnacut she was lent with her finger. And I KNOW she calls it like it is without any regard to repurcussions.

I take your points well, and as I say, if people over time really start to replicate that experience it'd be amazing and I'm very prepared to be convinced. As it stands, I don't think it's reasonable to say magnacut is equivalent to k390 when there's almost no evidence to suggest this by any meaningful standard, including the tests of the steels' own formulator. I think you might really be on to something when it comes to the medium of C&A's tests though, it may be that MC is particularly excellent at dealing with those kinds of media! There's also the basic reality that edge holding and cutting ability have, idk, 10x more to do with angle/edge than with steel, though obviously different steels like and respond differently to different edges

I had the video you linked in mind. I was surprised by those results as C&A appeared to be, and there's no question: they happened. But I'm basing my estimation of magnacut on A.) my own magnacut mule's performance, B.) Larrin Thomas' own CATRA tests and accounts of the steel he personally co-developed and tested in the most controlled way I've seen presented so far, C.) iirc the interesting but not super generalizable results BBB(?) got testing it alongside some others, including a cru-wear knife that 'outperformed' it (so to speak), and D.) the long-standing and massive opportunities folks have had to use m4 at a pretty wide array of heat treats, situations, angles, etc. I can't think of a thing to complain about with MC, which is the most remarkable thing about it in a way - it just doesn't suck at anything, and appears to be (relatively speaking, depending on use case) set up to be good to great at pretty much everything.

My own direct experience with MC is underwhelming, but again, even if it's a lot more 'data points' so to speak, it's a single person with a single knife and not much can be extrapolated. For a 5 month period, I used nothing but my mule for food prep while relocated for a job. Nobody in their right mind would suggest a mule is an ideal kitchen knife, so, all qualifiers and grains of salt included. But my mule chipped quickly and often despite being used on soft objects and wooden/plastic boards exclusively, and honestly, dulled surprisingly quickly [inb4 'factory edges,' which is truly a fake idea, and irrelevant anyway due to resharpening]. I compare this experience with a generic stainless 6" kitchen knife with similarly thick geometry (for kitchen uses), which performed roughly equally in terms of efficacy, dulling, and chips.

So again, I'm ready to discover it really is all that you appear to hope it is, but until there's more evidence across the board, all of the above & more suggest to me, at least, that there's a lot of hyperbole. I expect the reality to be a little more modest, if still by comparison kind of amazing, and I'm still prepared for something genuinely gold to emerge from all the glitter. Lemmy knows I wouldn't blink at snagging an *actual* kitchen knife in MC to try, despite my experience.

Hey guys, Gabe here (I sharpened the dual grit MagnaCut Mule that Pete tested). I think with regards to whether in a general sense MagnaCut's performance exceeds the steels you listed, my ability to comment is limited. I am very familiar with M4 but I'm just now getting some experience under my belt with K390 and MagnaCut.

In my personal opinion Pete's testing overall seems very consistent, but there are a few dynamics which affect this particular test you may not be aware of:

1: Dr. Todd Simpson wrote an article on dual grit sharpening and noted that it creates a highly textured extension of metal beyond the apex (for lack of a better term, a surprisingly stable sharpened burr which has aggression like a coarse edge, and extends above the apex - simulating a more acute edge angle, while also working to slow down the widening of the apex by abrasion). In the article he noted that the small dual grit apex extension corresponds in size (~10 microns tall) roughly to the width of a Sisal rope fiber (~10 microns wide). Essentially this means that my sharpening method effectively "hacks" or cheats slightly in rope cut tests because the portion of the edge which separates the rope fibers is thinned out to get through them more easily (than other edges at the same sharpening angle) and is also aggressive textured to reduce the amount of force it takes to initiate a cut.

2: The article also shows that the steel present at the edge has been moved by the coarse stone and re-centered by the fine. The fact that the steel at the apex has been moved means that steels in which the carbides are predominantly separated from one another will perform better with a dual grit edge, because there will not be cracking or separation of carbides in the apex. In this regard MagnaCut is a fairly ideal steel to gain the full benefit of dual grit sharpening.

3: Pete tested M4 with my dual grit edge and it did 1050 cuts, but I have gotten better at cleaning up damaged metal from the edge since then, and would probably be able to increase that number if I was to test M4 now.

For these 3 reasons, I think you should slightly adjust the test numbers in your ming to be closer to the other steels listed - as my edge kinda "hacks the test", and MagnaCut steel kinda "hacks my edge" so it's a fairly "fully optimized" set of circumstances.

I do think that dual grit sharpening can push the wear resistance of tougher steels like MagnaCut closer to the level of normal edges on high edge-retaining steels like K390, but it should be noted that the extra edge retention is probably a slight trade-off, as the edge stability is most likely lessened a bit (you give up a bit of edge toughness to gain a bit of edge retention with my method).

Does that make sense? Just want to validate and add to your discussion. If you want to check out the article I am referencing, link below:

https://scienceofsharp.com/2021/06/15/d ... harpening/

[hambone56rx]

I have a SM, CBN rods and a Wharncliffe Endela in k390. I’m no expert and put but an amazing edge on it. LOVE k390! Better than Cruwear right now for me. S30V has been the hardest for me to put an edge on in my experience. Took steels FTW!

Hamilton

[Wartstein]

..

...

I take your points well, and as I say, if people over time really start to replicate that experience it'd be amazing and I'm very prepared to be convinced. As it stands, I don't think it's reasonable to say magnacut is equivalent to k390 when there's almost no evidence to suggest this by any meaningful standard, including the tests of the steels' own formulator. I think you might really be on to something when it comes to the medium of C&A's tests though, it may be that MC is particularly excellent at dealing with those kinds of media! There's also the basic reality that edge holding and cutting ability have, idk, 10x more to do with angle/edge than with steel, though obviously different steels like and respond differently to different edges

I had the video you linked in mind. I was surprised by those results as C&A appeared to be, and there's no question: they happened. But I'm basing my estimation of magnacut on A.) my own magnacut mule's performance, B.) Larrin Thomas' own CATRA tests and accounts of the steel he personally co-developed and tested in the most controlled way I've seen presented so far, C.) iirc the interesting but not super generalizable results BBB(?) got testing it alongside some others, including a cru-wear knife that 'outperformed' it (so to speak), and D.) the long-standing and massive opportunities folks have had to use m4 at a pretty wide array of heat treats, situations, angles, etc. I can't think of a thing to complain about with MC, which is the most remarkable thing about it in a way - it just doesn't suck at anything, and appears to be (relatively speaking, depending on use case) set up to be good to great at pretty much everything.

My own direct experience with MC is underwhelming, but again, even if it's a lot more 'data points' so to speak, it's a single person with a single knife and not much can be extrapolated. For a 5 month period, I used nothing but my mule for food prep while relocated for a job. Nobody in their right mind would suggest a mule is an ideal kitchen knife, so, all qualifiers and grains of salt included. But my mule chipped quickly and often despite being used on soft objects and wooden/plastic boards exclusively, and honestly, dulled surprisingly quickly [inb4 'factory edges,' which is truly a fake idea, and irrelevant anyway due to resharpening]. I compare this experience with a generic stainless 6" kitchen knife with similarly thick geometry (for kitchen uses), which performed roughly equally in terms of efficacy, dulling, and chips.

So again, I'm ready to discover it really is all that you appear to hope it is, but until there's more evidence across the board, all of the above & more suggest to me, at least, that there's a lot of hyperbole. I expect the reality to be a little more modest, if still by comparison kind of amazing, and I'm still prepared for something genuinely gold to emerge from all the glitter. Lemmy knows I wouldn't blink at snagging an *actual* kitchen knife in MC to try, despite my experience.

Hey guys, Gabe here (I sharpened the dual grit MagnaCut Mule that Pete tested). I think with regards to whether in a general sense MagnaCut's performance exceeds the steels you listed, my ability to comment is limited. I am very familiar with M4 but I'm just now getting some experience under my belt with K390 and MagnaCut.

In my personal opinion Pete's testing overall seems very consistent, but there are a few dynamics which affect this particular test you may not be aware of:

1: Dr. Todd Simpson wrote an article on dual grit sharpening and noted that it creates a highly textured extension of metal beyond the apex (for lack of a better term, a surprisingly stable sharpened burr which has aggression like a coarse edge, and extends above the apex - simulating a more acute edge angle, while also working to slow down the widening of the apex by abrasion). In the article he noted that the small dual grit apex extension corresponds in size (~10 microns tall) roughly to the width of a Sisal rope fiber (~10 microns wide). Essentially this means that my sharpening method effectively "hacks" or cheats slightly in rope cut tests because the portion of the edge which separates the rope fibers is thinned out to get through them more easily (than other edges at the same sharpening angle) and is also aggressive textured to reduce the amount of force it takes to initiate a cut.

2: The article also shows that the steel present at the edge has been moved by the coarse stone and re-centered by the fine. The fact that the steel at the apex has been moved means that steels in which the carbides are predominantly separated from one another will perform better with a dual grit edge, because there will not be cracking or separation of carbides in the apex. In this regard MagnaCut is a fairly ideal steel to gain the full benefit of dual grit sharpening.

3: Pete tested M4 with my dual grit edge and it did 1050 cuts, but I have gotten better at cleaning up damaged metal from the edge since then, and would probably be able to increase that number if I was to test M4 now.

For these 3 reasons, I think you should slightly adjust the test numbers in your ming to be closer to the other steels listed - as my edge kinda "hacks the test", and MagnaCut steel kinda "hacks my edge" so it's a fairly "fully optimized" set of circumstances.

I do think that dual grit sharpening can push the wear resistance of tougher steels like MagnaCut closer to the level of normal edges on high edge-retaining steels like K390, but it should be noted that the extra edge retention is probably a slight trade-off, as the edge stability is most likely lessened a bit (you give up a bit of edge toughness to gain a bit of edge retention with my method).

Does that make sense? Just want to validate and add to your discussion. If you want to check out the article I am referencing, link below:

https://scienceofsharp.com/2021/06/15/d ... harpening/

Interesting findings and points, thanks for sharing!