Magnacut: The Story of a Modern Super Steel

In the world of knives, few words excite steel enthusiasts and casual users alike as much as Magnacut. It has become something of a legend in a short time, a steel that seems to do everything right. Toughness, edge retention, corrosion resistance, the trifecta that knife makers have chased for decades. But where did it come from, and what makes it special?

To answer that, you have to start with its creator, Dr Larrin Thomas, metallurgist, writer, and the mind behind Knife Steel Nerds. Thomas didn’t work for a steel company when he developed Magnacut. He wasn’t part of a corporate R&D team. He was simply a passionate metallurgist with a love for knives and an idea that wouldn’t let go.

A Dream Forged in Curiosity

Thomas grew up in the early 2000s, a time when steels like S30V were making waves. Crucible Industries had just launched it, and for the first time a steel was marketed as being “designed specifically for knives.” To a young metallurgist in the making, that was fascinating. What exactly made a knife steel different from tool steel or die steel? Why did it matter?

That question stayed with him. Years later, while working in the automotive industry developing advanced steels for cars, Thomas began researching knife steels in his spare time. He wrote detailed articles, analysed compositions, and interviewed metallurgists. But at some point, analysis wasn’t enough. He wanted to create something himself, to design a steel that solved the compromises knife makers had accepted for years.

The Big Idea

Every knife steel is a balancing act between three key properties:

• Toughness – how well the steel resists chipping and breaking

• Edge retention – how long it stays sharp

• Corrosion resistance – how well it fights rust

The problem is, improving one usually comes at the expense of another. Stainless steels are great at resisting rust but often sacrifice toughness. Non-stainless tool steels can be incredibly tough but tend to rust if you so much as look at them in a humid environment.

Thomas wondered, could you have both? Could you design a stainless steel with the toughness and edge performance of the best non-stainless tool steels? That question became the inception of Magnacut.

Designing the Impossible

The breakthrough came when Thomas rethought one of the long-held assumptions about stainless steels. Most stainless alloys use large amounts of chromium, usually between seventeen and twenty percent, to prevent rust. The problem is that too much chromium forms chromium carbides, large and relatively soft particles that hurt toughness and wear resistance.

So Thomas flipped the script. He designed a steel with less chromium but carefully balanced it with vanadium, niobium, and a touch of nitrogen. The chemistry of Magnacut was developed to promote the formation of good carbides, harder carbides, leading to a fine and even microstructure that is both strong and stainless.

In other words, he found a sweet spot, enough free chromium in solution to prevent rust, enough carbon for hardness, and just the right mix of other metals to boost wear resistance and toughness through the formation of vanadium carbides. The result was a stainless steel that didn’t behave like one. When Crucible Industries agreed to make a test batch, it was a leap of faith, and the rest, as they say, is history.

It's worth mentoning also that Thomas did more than just develop another steel for the knife industry. He empowered consumers by giving the industry a very specific and well researched HRC range, 62-64 HRC. Large scale heat treatment is a difficult task and some manufacturers will 'low-ball' HRC to ease manufacturing costs and challenges, they are often secretive about their target HRCs and/or will try to market their sub-optimal heat treatment as a purposeful prioritisation of toughness characteristics over edge retention. Thomas gave us all a big stick to hit these unscrupulous manufacturers with by determining the optimal heat treatment range for edge retention AND toughness.

"Fun Fact - Thomas named his creation CPM Magnacut, “Magnacut” as a nod to the high-speed steels of old that carried names like Vasco Wear and HyperCut. Magna – Latin for “great” – was both a wink to history and a bold statement about what this new steel aimed to be." - Mr. Narwhal 

How It Performs

When the first knives were made in Magnacut, the results were astonishing. It outperformed nearly every stainless steel available at the time.

Toughness: Comparable to non-stainless favourites such as CPM 4V and CruWear, steels known for their resilience in demanding knives.

Edge retention: Excellent, on par with the best balanced steels.

Corrosion resistance: Better than expected, in some tests even exceeding high-chromium steels like 20CV.

This last point was perhaps the most surprising. By eliminating chromium carbides, Thomas had actually improved corrosion resistance, since the chromium stayed in solution rather than being trapped in undesirable chromium carbides. The result was an indomitable stainless steel that laughed in the face of saltwater.

The Knife Maker’s Perspective

Knifemakers who tried Magnacut quickly realised it wasn’t just a metallurgical marvel, it was a joy to work with. It grinds and finishes more easily than S35VN, sharpens beautifully, and takes a razor edge that holds and holds. Whether used for a chef’s knife, a survival blade, or a folding everyday carry, it simply works.

It also sharpens easily, even on conventional stones, and responds well to stropping. For users, that means less frustration and more cutting. In our opinion here at ArcticKnife, Magnacut has affectively obsoleted S30V, S35VN and S45VN.

A Balanced Revolution

If you imagine the world of knife steels as a triangle with toughness, edge retention, and corrosion resistance at each corner, most steels sit somewhere along one edge. Magnacut, somehow, sits in the middle. It doesn’t demand compromise.

That’s why it has been described as the most well-balanced knife steel ever created. It’s not the hardest, or the most wear-resistant, or the most stainless, but it is excellent in all three categories. It’s a steel for real-world knives, knives that are used, not just admired.

More Than Metal

At its heart, Magnacut isn’t just a new alloy. It’s a reminder of what happens when passion meets persistence, when someone outside the corporate machine dares to rethink the rules.

Dr Larrin Thomas didn’t set out to make a “super steel” for marketing hype. He wanted to make something better, something more balanced. And in doing so, he changed the conversation about what stainless steel could be.

In Summary

Creator: Dr Larrin Thomas
Manufacturer: Crucible Industries, now EraSteel
Key properties: High toughness, excellent corrosion resistance, outstanding edge stability
Best comparison: The toughness of CPM-4V with the stainless performance of M390/CPM-20CV/CTS-204P
Ideal use: Almost everywhere. Everyday carry knives, kitchen knives, outdoor blades, anywhere performance and reliability matter.

Conclusion

In a world obsessed with extremes, the hardest, the sharpest, the rarest, Magnacut stands for something rarer, balance. It is a steel that does everything well without demanding sacrifice. And for that reason, it’s not just another alloy on a datasheet. It’s a landmark, a steel that redefined what stainless can mean for knife makers and users alike.

Next week we'll dive into a MagnaMax, Larrins new steel. If Magnacut is a tough stainless, MagnaMax is a super edge retention stainless.... think stainless K390.