Medford Knife & Tool · Steel Philosophy

The Medford Knife
Steel Guide

How Greg Medford thinks about steel — and why he picks the ones he does.

Greg's Framework

The Steel Triangle

You can't get any one of those three really high without sacrificing the others. Max hardness means toughness degrades. Max toughness means softening something elsewhere. The job is to find the right balance for the application — and Greg reverse-engineers from the end use of the knife to get there.

At Medford, every steel is hardened way above the target range in-house, then tempered back to the sweet spot — 59 to 61 HRC. Hard enough to maintain a great edge. Not so hard you can't put an edge back on it yourself. "61 is getting to be almost too hard," Greg says. "57 is a little too soft."

Because Medford knives are built thick — nominally over a quarter-inch for folding blades — geometry makes up for a lot. Greg doesn't have to chase the penultimate molecular strength out of the steel. He can focus on the intersection of toughness, hardness, and corrosion resistance rather than maxing one at the expense of the others. When the end use demands something specific, he picks the steel to match it.

The Materials

The Steels We Use

The knives currently offered in each steel — and where the philosophy came from.

Watch The Full Breakdown

Metallurgy 101
with Greg Medford

19 minutes of unscripted metallurgy talk — from how heat treat actually works to why Greg picks the steels he does and how to think about the tradeoffs.

Greg's Full Philosophy

How to Think About Knife Steel

Not All Steel Philosophy Is Equal

There are wonderful knives made out of the most primitive metals on earth. And there are crappy knives made out of some of the best metals walking the planet — with a whole lot of everything in between. The steel you choose doesn't automatically make a good knife. Greg Medford has been making knives long enough to know that the conversation about steel is rarely as simple as "this one is better than that one."

The Application Drives the Choice

Every time you make a decision about the steel you choose to make knives out of, there are pros and cons. The right steel for a professional kitchen is not the right steel for a heavy tactical fixed blade — and neither is the right steel for a machete going into a saltwater marine environment.

A kitchen knife is going to be used more than a tactical knife will ever be used — every single day, around water, salty fluids, and blood from meat, by people who will set it on a ceramic plate or a stone countertop without thinking twice. That pushes you toward a steel that's corrosion resistant and sits on the softer side of the hardness range, because it'll be honed or stropped regularly and sharpened a couple of times a year.

A big, heavy, utilitarian tactical tool — the kind of knife Greg makes — is a different animal entirely. Greg reverse-engineers from the end use: what is this knife going to be asked to do, and what does that demand from the steel?

"I try to look at the end application of the knife and I kind of backwards end up — I reverse engineer to end up at what the best deal is for that application."

— Greg Medford

The Three Things You're Actually Balancing

Greg keeps a mental triangle when he talks about steel. Three properties — toughness, hardness, and abrasion/corrosion resistance. Every steel sits somewhere on that triangle. The problem is that you can't push any one of them to the extreme without sacrificing one or both of the others.

Toughness is how much shock, smack, pry, and displacement the steel can take — and still spring back or hold its shape. How much can you displace it and have it permanently deform? How much can you bend it back and still have it function? Hardness is whether you can get the steel hard enough during heat treat — and then draw it back to a point where it'll hold a great edge without being so brittle a guy can't resharpen it himself. Abrasion and corrosion resistance live in similar territory at the microscopic level: how well does the steel resist being worn down, scratched, or oxidized — especially at the edge where the knife is most exposed.

The job isn't to find the steel that wins in one of those categories. The job is to find the steel that lands in the right place on all three for the way the knife is going to be used.

The Hardness Sweet Spot — and Why Extremes Fail

Greg tests every knife, every batch, on the Rockwell scale. His target landing zone is 59 to 61 HRC — regardless of the steel. "61 is getting to be almost too hard. 59 is great. 58 it's okay. 57 is a little too soft in my opinion."

The upside of a really hard knife is that it'll hold an edge. The downside is that when you inevitably make it dull — and you will — it's genuinely hard to put an edge back on. There are knife companies that make steels so hard you have to send them somewhere to get sharpened once a year. That might work if the knife is going to be used gently and carefully for the rest of the year. For a working tool that's going to see real use, it's a problem.

"You don't want to make a knife so hard that a guy can't resharpen it. We need it in that kind of sweet spot of 59 to 61."

— Greg Medford

Heat Treat Is Half the Equation

Choosing the right steel is only part of the story. How you heat treat it matters just as much — or more. What temperature do you heat it to? How long do you soak it at temperature? How do you quench it — salt bath, oil, vacuum, air? Do you quench in Inconel or out of it? At what rate? When do you begin warming it back up to temper? How many times do you temper it, and at what temperature?

All of that is worked out in a recipe by the original engineer who designed the steel — but how the knife maker actually applies that recipe in his shop is his part of the metallurgy equation. Greg does all heat treating in-house. Every steel he works with gets hardened well above the target zone, then tempered back down through multiple cycles to land in that 59–61 HRC sweet spot. The harder you make it, the less tough it becomes. So you go high, then you carefully bring it back.

The more exotic and high-performance a steel gets, the narrower the margin of error on temperature, soak time, and handling becomes. That's one of the things Greg weighs when he decides whether to work with a given steel. A steel that requires exotic post-process treatment — vacuum chambers, specialty handling that has to go somewhere else — adds cost and complexity to every single knife that goes through it.

Why Geometry Changes the Math

Medford knives are built thick — nominally over a quarter inch for folding blades. That changes what you need to demand from the steel at the molecular level. When your geometry is doing structural work, you don't need to chase the penultimate strength out of the material itself. You can pick for the intersection of all three triangle properties rather than having to sacrifice two of them to get one really high.

Guys who make dainty knives are often picking for much more constrained requirements — they can go to a very different building material than a guy making big, heavy, utilitarian tools. Greg makes knives that are meant to be worked and used, by people who may use them for everything they need out in the field — prying, chopping, slicing, and everything in between. The geometry is designed with that reality in mind.

Why D2 — and What "Good at Everything" Really Means

D2 is a tool steel that's been around a long time. Ask any old-timer who makes knives about D2 and they'll tell you it takes a great, predictable heat treat. It's one of the easiest metals to heat treat really well. The more exotic and high-performance a stainless steel gets, the harder and harder it is to get a good, predictable heat treat out of it — you can do it, but the margin of error on temperature and timing gets narrower and narrower.

D2 sits at the intersection of corrosion resistance, toughness, and hardness. "It's not the best at anything, but it's really good at everything." Greg typically gets D2 to 65–66 HRC in treatment — he's seen it hit 67 — and then draws it down to 59–61 during tempering. Consistent, reliable, repeatable.

Why CPM 3V Exists in the Lineup

CPM 3V is a different animal. It never gets quite as hard in Greg's process — he brings it to the 58–59 HRC range — but the toughness is exceptional. "The stuff's unbelievably tough." For customers who specifically need the penultimate tough knife, CPM 3V is the answer.

The trade-off is corrosion resistance. If Greg makes a really tough CPM 3V knife, he's got to do expensive post-processing to make it corrosion resistant — and then once you polish the edge, the edge can rust. It's a "damned if you do, damned if you don't" situation for most customers, who need a tough knife that is also reasonably corrosion resistant. For the subset of customers who have read every steel comparison ever published and specifically want 3V, Medford offers it — with an upcharge that reflects the extra cost of running a different steel through the production chain.

Why S35VN for Corrosion-Critical Applications

When Greg is making knives for Naval and marine applications — environments where the knife is going to live in a saline environment, or where the design of the knife makes it hard to get in and properly clean internal parts — he reaches for S35VN. The corrosion resistance is the primary driver.

On the S30VN vs S35VN debate: the two steels have essentially the same corrosion resistance — the five-point vanadium difference in S35VN was engineered for a practical commercial grinding reason, not for performance. On a production grinder using a commercial grinding stone, the frequency of vibration in S30VN matches the density of the stone and it chatters. The vanadium carbides in S35VN shift the wavelength so it doesn't chatter on a Blanchard or Mattison grinder. Since Medford freehand grinds — no production grinders, no commercial grinding stones — the chatter issue simply doesn't apply. The corrosion resistance is what matters, and on that measure the two steels are nominally equivalent.

Why S7 for Machetes and Heavy Work

S7 is a shock-resistant tool steel — and that spring quality is what Greg values it for. When he's making machetes for customers going into places where corrosion resistance is less of a concern than raw toughness and the ability of the blade to absorb impact, flex, and come back, S7 is the material. The priority is different: it's not about holding a mirror-polished edge, it's about surviving hard use in demanding environments.

On Steel Fads and "Magic Superman Metal"

Knife magazines drive steel fads. If you're a large company and your products are uninspiring, you can sell the new greatest whiz-bang steel instead. Greg likens it to someone who says they know the death touch — you can't prove it or do it, but you can say it, and it trumps whatever the other guy has. "I've got the special steel. It's secret." It's a way to compete on marketing rather than on design.

"If you don't have a new inspiring design or you don't have a new product that people really want, maybe you can sell them that it's got some metal — some magic Superman metal. And I don't want to buy it."

— Greg Medford

The Bottom Line

Greg has landed on a handful of steels he considers the best bang for the buck — the best performance for the dollar, and the best end usability for the customer. Not getting too crazy and exotic. Not being so rigid that he thinks one steel is better than all the rest and everything else is wrong. He doesn't think that way.

He thinks: I'm making a tool for this kind of use. Here's how I know guys actually use knives. I don't want to make safe queens. So he picks the steel that serves those guys — the ones who'll work the knife, use it for everything they need, and want to be able to sharpen it themselves when the edge comes off.

That's the whole philosophy. Not the most exotic steel. Not the hardest. Not the one with the most syllables in its name. The right one for the knife, the use, and the person who's going to carry it for the next twenty years.

The Knives

Browse
All Models

↗

Fixed blades, folders, and everything built in the Phoenix factory.

The Craft

How We
Build Them

↗

See the full manufacturing process — from blank to finished knife.

The Man

About
Greg Medford

↗

The founder, the vision, and why he built it the way he did.