[bob_loblaw]

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]

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]

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.

[spekcular]

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.

[bob_loblaw]

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

[mafm]

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.

[rdtwo]

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]

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]

There is a fantastic place in Seattle that does it at 2$ an inch or something. Just takes about a month

[kragen]

Hmm, is vanadium carbide really harder than tungsten carbide, even at room temperature?

[bob_loblaw]

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]

Interesting, thanks!