MagnaCut Steel: The Complete Guide for Knife Owners

CPM MagnaCut is a powder metallurgy stainless steel engineered specifically for knives. It combines the toughness of non-stainless tool steels like CPM-4V, the corrosion resistance of marine-grade stainless steels like LC200N, and edge retention competitive with S35VN and S45VN.

No other knife steel matches this combination. Metallurgist Dr. Larrin Thomas designed MagnaCut to eliminate the trade-offs that have frustrated knife makers and owners for decades, and the metallurgy backs up the claim.

At Montana Knife Company, we use MagnaCut steel for the majority of our lineup, from ultralight backcountry hunting knives to tactical blades and culinary tools. We sat down with Dr. Thomas himself to dig into the science, the story, and the practical details that put MagnaCut steel in a class of its own.

What Is CPM MagnaCut Steel?

For years, knife makers and enthusiasts accepted a frustrating trade-off: you could have a tough blade, excellent edge retention, or corrosion resistance, but never all three. Then Dr. Thomas did what no one thought was possible: he designed a knife steel that delivered on all fronts.

Unlike most blade steels derived from industrial applications, Thomas engineered CPM MagnaCut steel from the ground up to address weaknesses in other knife steels. That might sound like marketing speak, but the metallurgy backs it up.

MagnaCut’s origins trace to trips to knife shows. Dr. Thomas grew up in the knife world: his father, Devin Thomas, was known for his work with Damascus steel.

“These trips gave me a lot of interaction with knife makers,” Thomas explains. “They would say they had secret steel, better steel, and special heat treatments that led to better steel properties than other knife makers. Intrigued, I started studying how steel was made.”

That curiosity led to a PhD in metallurgical engineering and work as a steel metallurgist. Eventually, Thomas spotted an anomaly when plotting toughness versus wear resistance for existing stainless steels: a large gap in the chart where a better steel could exist.

He contacted Crucible Steel with his idea. They had questions. Lots of them. Thomas supplied experimental data and predictive models, but as he puts it, “You never really know if a new development will work until you try it.”

MagnaCut steel came out of its first heat working exactly as predicted. The corrosion resistance turned out even better than Thomas had expected.

CPM MagnaCut Composition and Metallurgy

To understand what makes MagnaCut steel special, start with the chemistry.

The key innovation is in the chromium. Traditional stainless knife steels contain 14 to 20% chromium, but much of that chromium gets locked up in chromium carbides that can’t actually fight corrosion. Thomas reduced the chromium to around 11% and balanced the composition so that all of it stays “in solution” to form a protective chromium oxide layer.

“My idea was to reduce the chromium content down to the actual chromium we needed in solution,” Thomas told us. “About 11%, right in the middle of that 9 to 13% effective range, and then adjust the rest of the composition so we didn’t have extra chromium carbides after heat treatment.”

Instead of chromium carbides, MagnaCut steel uses vanadium and niobium carbides. These are harder than chromium carbides, so you get better wear resistance with fewer, smaller carbide particles. The result is a steel that behaves like the best non-stainless tool steels while maintaining the corrosion resistance of stainless.

Production update: Crucible Industries originally produced MagnaCut steel. Production has since transitioned to Erasteel, and independent testing by Dr. Thomas shows the Erasteel version matches or exceeds the original in toughness and corrosion resistance.

MagnaCut HRC Hardness: What the Numbers Mean

MagnaCut can be heat-treated anywhere from 59 to 64 HRC (Rockwell C hardness). This flexibility lets knife makers dial in the exact balance of properties for different applications.

“Anywhere between 59 and 64 on the Rockwell hardness scale can work great,” Thomas explains. “I know some out there give specific hardness targets they think are ideal or claim a knife is no good below a certain hardness. But I feel that ignores the balance you get at different hardness points.”

Most production MagnaCut knives, including ours at Montana Knife Company, run in the 61 to 63 HRC range. This gives excellent edge-holding capability while maintaining the toughness that makes MagnaCut steel special.

MagnaCut Steel Performance: Edge Retention, Toughness, and Corrosion Resistance

Edge Retention. MagnaCut steel’s edge retention falls between S35VN and S45VN in standardized CATRA testing. That might not sound revolutionary, but those tests only measure abrasion resistance. Real-world edge retention depends on toughness, too.

A blade that chips or rolls under pressure loses its edge regardless of how wear-resistant the steel is. MagnaCut’s fine carbide structure means the edge degrades gradually through wear rather than suddenly failing. In practical use, many owners find MagnaCut steel holds a working edge longer than steels that score higher on pure abrasion tests.

Toughness. This is where MagnaCut steel really separates itself from other stainless steels. The absence of large chromium carbides and the fine, evenly distributed vanadium and niobium carbides give MagnaCut steel toughness comparable to non-stainless tool steels like CPM-4V.

In Charpy impact testing at 62.5 HRC, MagnaCut steel delivers approximately 38 ft-lbs of toughness. That’s roughly 40% tougher than S35VN at similar hardness and competitive with dedicated “tough” steels. What does this mean in practice? Thin edges won’t chip on bone. Fixed blades can handle batoning. You can have the confidence to actually use your knife without babying it.

This toughness also enables better blade geometry. Because MagnaCut steel can take more abuse, we can grind blades thinner than other stainless steels allow. Our Speedgoat 2.0 runs a blade thickness of just 0.095″, and the Mini Speedgoat 2.0 gets down to 0.090″. Thinner geometry means the cutting edge has less material behind it, so the blade slices more efficiently and the edge stays sharper longer in real-world use.

Corrosion Resistance. Despite having less chromium than most stainless steels, MagnaCut steel’s corrosion resistance is excellent, approaching specialized marine steels like LC200N.

The reason goes back to that chromium carbide elimination. In traditional stainless steels, the areas around chromium carbides have reduced free chromium, making them easy starting points for rust.

MagnaCut steel doesn’t have those weak spots. When you’re dealing with blood, moisture, and field conditions, this corrosion resistance is critical.

How MagnaCut Steel Compares to Other Premium Knife Steels

MagnaCut vs. S35VN: S35VN has long served as the industry standard for balanced performance. MagnaCut steel delivers similar edge retention but roughly 40% more toughness and better corrosion resistance.

MagnaCut vs. S30V: S30V was the original “super steel” that got knife enthusiasts excited about powder metallurgy. It has good edge retention but chips more easily than MagnaCut steel because of its larger carbide structure. MagnaCut matches S30V’s wear resistance while delivering much better toughness and corrosion resistance.

MagnaCut vs. M390/20CV: M390 and its near-identical counterpart 20CV win on pure edge holding, but they’re prone to micro-chipping on hard impacts. Their higher carbide volume creates a more brittle microstructure. MagnaCut steel trades a bit of wear resistance for better toughness, making it more forgiving in hard use. MagnaCut also matches or exceeds M390’s corrosion resistance because its chromium stays in solution rather than getting locked up in carbides.

MagnaCut vs. S90V: S90V is the edge retention king. Its 9% vanadium content creates a massive volume of hard carbides that resist abrasion longer than almost any production steel. In CATRA testing, S90V scores roughly 195% vs. 440C baseline, while MagnaCut steel scores around 135%. If maximum cuts between sharpenings is your only priority, S90V wins.

The trade-off is severe: S90V is three to four times less tough than MagnaCut steel, chips easily at thin edge geometries, and is notoriously difficult to sharpen. We tested early Blackfoot prototypes in S90V, and they snapped like glass when we tried to grind them thin enough to perform the way we wanted.

MagnaCut vs. CPM-3V: CPM-3V is legendary for toughness, but it isn’t stainless. MagnaCut steel matches 3V’s toughness while adding genuine corrosion resistance. For wet environments or low-maintenance use, MagnaCut is the clear choice.

MagnaCut vs. 52100: Montana Knife Company sells both. “52100 steel has a little more toughness than MagnaCut steel, and MagnaCut has more wear resistance,” Thomas notes. Carbon steels like 52100 are also easier to sharpen, but they require more maintenance.

Choose 52100 if you prefer a razor-sharp carbon edge and don’t mind wiping and oiling your blade. Choose MagnaCut if you want stainless, low-maintenance performance.

MKC MagnaCut Knives Across the Lineup

MagnaCut steel’s versatility is one reason we’ve built so much of our lineup around it. Here’s how we use MagnaCut steel across different categories:

Hunting. From the Blackfoot 2.0 (3 3/8″ blade, 3.6 oz) as our do-it-all hunter, to the Speedgoat 2.0 (3 3/4″ blade, 1.7 oz) for ultralight backcountry packing, to the Whitetail (4″ blade, 4.49 oz) built specifically for deer, to the Super Cub (5.5″ blade, 5.94 oz) for elk-sized game. MagnaCut’s toughness lets us grind these blades thin for efficient cutting, while the corrosion resistance handles blood, rain, and days without cleaning.

Tactical. The TF24 (4 1/8″ blade, 0.158″ thick) and Redacted (4 7/8″ blade, 0.170″ thick) use Cerakoted MagnaCut for demanding tactical and survival applications. The Fieldcraft Survival Knife brings MagnaCut to the EDC self-defense category.

Culinary. MagnaCut’s balance of edge retention and corrosion resistance makes it an excellent kitchen steel. Our Bighorn Chef (7 3/4″ blade), Shedhorn Chef (6 1/2″ blade), and Smith River Santoku (6 3/4″ blade) all use MagnaCut, giving home cooks and outdoor chefs a blade that handles acidic foods, moisture, and extended prep sessions without losing its edge.

EDC and Utility. We built the Badrock (3 1/8″ blade, 1.85 oz) from the ground up for true pocket carry. The Flattail, Jackstone, and Rocker round out our MagnaCut EDC options for owners who want a compact, low-maintenance daily blade.

How to Sharpen and Care for MagnaCut Steel

MagnaCut steel sharpens more easily than many high-performance stainless steels. The absence of large, hard chromium carbides means less material fighting your stones:

• Diamond plates work the fastest and most efficiently on MagnaCut. Coarse diamond (around 300 to 400 grit) quickly restores a dull edge, while finer grits polish it.
• Ceramic rods handle field touch-ups well.
• Traditional waterstones work, though some users note MagnaCut feels different on them compared to other steels.

Diamond or CBN stones give the most consistent results.

As for sharpening angle, Thomas suggests experimenting: “Go with a more acute angle that’s going to cut a lot better. If you find you’re starting to get some micro-chipping, then back off on that angle some, and you’ve found the sweet spot for exactly how you like to use and sharpen your knife.”

Most MKC MagnaCut knives ship with a factory angle of around 17 to 20 degrees per side. Every MKC knife also comes with our MKC Generations® promise, which includes free resharpening for life, if you’d rather not resharpen it yourself.

For daily care, rinse with clean water after use (especially after contact with blood, saltwater, or acidic foods), wipe dry, and store clean. A light coat of MKC blade wax adds extra protection for long-term storage.

Is MagnaCut Steel Worth It?

MagnaCut steel knives typically run slightly higher in price than equivalent designs in S30V or S35VN, but the premium is smaller than most people expect. The bulk of a knife’s price comes from design, manufacturing, handle material and type, and the maker’s process. Steel is a factor, but not as large a factor as many buyers assume.

That said, MagnaCut’s value shows up over time. You’ll spend less time sharpening, less effort on maintenance, and you’ll get a blade that tolerates thin geometry without chipping.

For hunters who process multiple animals per season, the combination of edge stability and corrosion resistance means the knife works hard and cleans up easily. For EDC users, the stainless steel performance means pocket moisture, food acids, and neglect won’t punish your blade.

Choose MagnaCut if you want a low-maintenance blade that performs across a wide range of tasks, hunt or work in wet conditions, value toughness and corrosion resistance alongside good edge retention, or want the option of thin, high-performance blade geometry.

Choose 52100 carbon steel if you prefer the sharpest possible edge and don’t mind regular maintenance, enjoy the ritual of caring for a carbon blade, or primarily use your knife in dry conditions where corrosion isn’t a concern.

Choose a pure edge-retention steel (S90V, M390) if you prioritize maximum cuts between sharpenings above all else, use your knife primarily for slicing tasks without hard impacts, and have the skill and equipment to sharpen very hard, high-carbide steels.

For most hunters, outdoor professionals, and EDC users, MagnaCut hits the best overall value. It doesn’t force you to choose which property matters most.

Frequently Asked Questions About MagnaCut Steel

What is MagnaCut steel?

CPM MagnaCut steel is a powder metallurgy stainless steel designed specifically for knives by metallurgist Dr. Larrin Thomas. It eliminates the traditional trade-off between toughness, edge retention, and corrosion resistance by using vanadium and niobium carbides instead of chromium carbides.

Is MagnaCut steel better than S30V?

MagnaCut steel is tougher and more corrosion-resistant than S30V, with comparable edge retention. S30V chips more easily because of its larger carbide structure. For most users, MagnaCut steel is the better all-around steel.

Is MagnaCut steel hard to sharpen?

MagnaCut steel sharpens more easily than high-carbide steels like S90V, M390, and S110V. Diamond plates work best, and ceramic rods handle field touch-ups well. Traditional waterstones work, but differently on softer steels.

Is MagnaCut steel stainless?

Yes. Despite having less chromium than most stainless steels (10.7% vs. the typical 14 to 20%), MagnaCut steel’s corrosion resistance is excellent because nearly all of its chromium stays in solution to form the protective passive layer. It approaches the corrosion resistance of marine-grade steels like LC200N.

What is MagnaMax?

MagnaMax is Dr. Thomas’s follow-up to MagnaCut, announced in early 2026. It increases edge retention to match steels like CPM-10V and K390 while maintaining the toughness and corrosion resistance that made MagnaCut famous.

Think of it as the high-edge-retention version of the same design philosophy.

How does MagnaCut compare to M390?

M390 (and its near-identical counterpart, 20CV) holds an edge longer than MagnaCut steel in pure abrasion testing. MagnaCut is much tougher, making it more forgiving during hard use and better at maintaining thin edge geometries without chipping.

MagnaCut steel also matches or exceeds M390’s corrosion resistance.

Final Thoughts on MagnaCut Steel

MagnaCut steel isn’t hype. It’s a genuine metallurgical achievement that gives knife users what they’ve asked for: a stainless steel tough enough to use hard, with edge retention and corrosion resistance that holds up in the field.

“I wanted to improve knife steel properties through better design and give people what they’ve been looking for,” Thomas told us. “And based on the feedback from knife companies and end users, I think CPM MagnaCut does that.”

We agree. That’s why we’ve built so much of our lineup around it.

With Larrin Thomas, a Knife Steel Metallurgist and Founder of Knife Steel Nerds