‘Super Blade’ Claims 10x Stronger, Sharper Steel: DiamondBlade Knives Summit Folder Review

The most important ingredient in a knife is its steel. DiamondBlade Knives claims its steel is the best and most balanced you can get, thanks to a unique forging process. 

DiamondBlade Knives’ “Friction Forged” D2 steel supposedly has 10 times finer steel grain than traditional D2. The brand says that process makes the edges of its knives harder, thinner, and tougher. The website claims its knives “will outperform any other knife by 10 times — or better — guaranteed.”

Those are big, bold claims. But DiamondBlade Knives developed this Friction Forged technology in collaboration with Brigham Young University (BYU). It’s patented, and clearly, the brand is confident in its qualities. So when I got my hands on a DiamondBlade knife, I was immediately itching to test it. The brand calls the Friction Forging knives “Super Blades,” after all.

I got the DiamondBlade Summit Folder a year ago (October 2023). Since then, I’ve used it to field dress my first whitetail deer, cut paracord on countless camping trips, chop veggies and meats, slice tops off beer cans, split wood, and make shavings for firestarter. I even started carrying it around as an everyday carry knife.

But does its Friction Forged D2 makeup make it 10 times better than every other knife on the market? The jury is still out. While some experts have expressed doubt, I’m not saying no just yet.

In short: The DiamondBlade Knives Summit Folder ($295) sports a 3.375-inch Friction Forged D2 blade and a G10 handle. It is a full-sized folding hunting knife that holds an edge remarkably well. In months of testing and daily use I haven’t seen a single spot of rust. This knife feels good, looks good, and seems to be as high quality as its makers claim. For its price, I’m glad that’s the case.

If you’re shopping for hunting and survival knives, check out our guide to the Best Survival Knives.

‘Super Blade’ Steel: A Disclaimer

Before I start, I need to note that GearJunkie couldn’t procure true metallurgy tests to confirm or refute DiamondBlades’ quantitative claims of its Friction Forged D2 steel.

I reached out to a local company that could test the blade, but the cost of testing a single knife for this review was prohibitively expensive. Without testing the steel, that metallurgist declined to comment on the brands’ claims.

I did speak with another knife and metal expert (you’ll hear from them shortly), but most of what follows are qualitative observations based on my own field testing. This knife saw a lot of hard everyday carry (EDC) use through a long camping season in the Rockies. It cut wood, paracord, cardboard, leather, deer flesh, human flesh (accidentally), food, plastic, aluminum, and more.

This has become the knife I put on my belt every morning.

What Is Friction Forged D2 Steel?

The DiamondBlade Knives website has an entire page dedicated to its Friction Forged process and the science behind making D2 steel into “Super Blades.” It gets deep in the weeds. The brand spent a lot of time and money on R&D for this tech. I’ll avoid getting too detailed, but it’s worth understanding why the brand claims that its Summit Folder is such a special knife.

Friction Forging uses a very specific tool made from Polycrystalline Cubic Boron Nitride (PCBN) to “penetrate the blade” as it rotates, creating frictional heating. That also allows the knife maker to achieve “differential heat treatment” — making the spine softer and blade edge harder with stainless and high-alloy steels. 

During the process, the PCBN tool moves along the piece of steel that will become the blade’s edge, continually forging it as it does so. That brings it to the “transformational temperature” that produces fine-grain steel structures. Those are so small, the brand claims, they can only be seen with electron microscopes.

DiamondBlade claims that the exceptionally fine grain of its Friction Forged D2 allows it to make a thinner, non-brittle blade with an ultra-hard, long-lasting edge. For materials nerds, that might sound too good to be true. Typically, harder steels are more brittle than softer steels. That is not the case with Diamond Blades’ Friction Forged Steel, the brand alleges.

DiamondBlade Knives Summit Folder Review

When I shot my first whitetail in Nebraska last fall, the Summit Folder was the knife I field-dressed it with. It made the process feel almost too easy, but that was right out of the box when the knife still had a factory-sharp edge.

I tried not to let those exciting first impressions go to my head as I continued using it. But the knife continued to impress me. While camping, I used it for everything from batoning wood to cutting paracord, slicing aluminum cans, and prepping veggies. I even used it as a steak knife one night. As a knife, the Summit Folder is an extremely effective tool for general camping purposes.

It has a satisfying 3.5-ounce weight. The handle is ergonomic and made from G1. In your hand, this knife feels very solid and wieldable.

I really appreciate the 3.375-inch blade length. It’s long enough to accomplish hardier tasks like splitting wood or field dressing. But because it’s a folder, it also isn’t too big for EDC. Length-wise, in my opinion, the Summit Folder hits the sweet spot.

Edge Retention

In the last year and a half, there have been two other primary folding knives I’ve used — both from prominent, recognizable knife brands. One of them used S30V steel, and the other used S35VN.

Unfortunately, I do not own another D2 steel-bladed knife with which to make a direct comparison. But I can tell you that the Summit Folder has kept a notably sharper edge than both of those other knives over similar testing periods.

I also don’t have an electron microscope. So I can’t tell you exactly how well the blade’s edge is holding up. I won’t say that it has remained as sharp as it was the day I got it. But it has definitely stayed sharper for longer than other knives I’ve used.

DiamondBlades provides data from its own CATRA “edge retention” tests on its webpage for Friction Forged. It claims this test showed that Friction Forged steel cuts “50% more material per stroke at the outset” and that it stayed sharper than the other knife steels DiamondBlades tested. A “strokes to dull” test indicated it maintained its sharpness after more cutting than other steels did.

However, just below that, DiamondBlades shows data from a “cutting life” test that shows Friction Forged steel actually performed worse than other steels. So even DiamondBlades’ own tests leave room for interpretation. It’s kind of hard to parse out.

If you want to see the data for yourself, scroll down to the “Testing” section on the Friction Forged Technology webpage.

Sharpening

I didn’t need to sharpen the Summit Folder, but “easy to sharpen” is one of DiamondBlade’s big selling points for its Friction Forged blades. So I had to try. I put it in a lineup with a couple of other pocket folders and two of my kitchen knives that needed a little whetstone love and made an evening of it.

Softer steels sharpen easier, and the bladed edge of the Diamond Blades knife has a hardness of 65-69 HRC, according to DiamondBlades — that’s compared to the typical 54–62 HRC hardness of regular D2 tool steel. It’s hard stuff. The honing progress is incremental, but it wasn’t prohibitively tough. It might just take a little longer, depending on how dull the blade has become.

It would pay off to hone this blade regularly so you don’t have to work too hard to regain its edge.

Handling

At 3.375 inches, the blade is a very functional length. It’s big enough to perform more significant tasks without losing maneuverability points. It’s relatively thin at 0.118-0.120 inches wide, which feels nimble in use compared to some chunkier blades I own.

A full inch of jimping on the spine of the blade offers some serious thumb control, too.

The G10 handle is comfortable, ergonomic, and easy to hold. It’s a surprisingly light knife for its size (3.5 ounces), but the weight feels good in your palm.

Action & Lock

The DiamondBlade Knives Summit Folder uses a traditional lock-back design. It’s simple. It doesn’t snap open easily with a flick of the wrist. But there is a small hex screw where the blade connects to the handle. If you really wanted to, you could loosen that slightly to make the action easier.

Overall, though, opening and closing this knife is smooth. There is no give or looseness in the blade, whether it’s open or closed.

Limited Carry Options

The Diamond Blades Summit Folder does not have a pocket clip. Instead, it uses a sheath. DiamondBlade Knives offers both nylon and leather options. The tooled leather sheath costs $20 more and has a nice, classy flair.

My only issue with it is that it’s bulky. It looks like you’re carrying a Palm Pilot on your belt. I ended up trimming the leather on the clip so it’s a little lower profile.

For people who carry multitools or cellphones on their belts, it won’t be a bother. But I’m not used to having something so big on my hip, and it kind of throws me off. I really wish this thing had a pocket clip.

There is a lanyard aperture on the handle, so you could wear it around your neck. But that might look and feel even weirder.

The advantage of the sheath? It’s nearly impossible to lose this knife. I’ve had folding knives with pocket clips that get snagged on jackets and yanked out. I’ve actually lost knives because of loose pocket clips. That’s never going to happen with the Summit Folder as long as it’s securely buttoned up in its sheath.

DiamondBlade Summit Folder Price

Folding knives are a broad category and their prices vary significantly. This folding knife is the exact same blade size and shape as DiamondBlade’s flagship fixed-blade, the Summit. Both versions of the Summit are classified as “hunting knives” and lean distinctly more toward survival applications than everyday carry (EDC).

Compared to the other knives on GearJunkie’s guide to the Best Survival Knives, the DiamondBlade Summit Folder is on the pricey end of the spectrum at $295. It would rank third for the most expensive blade on the list.

The most comparable knife on that list would probably be the Benchmade Anonimus, which uses Benchmade’s improved version of D2, which it calls CruWear. That fixed blade is slightly bigger than the Summit Folder, with a full length of 9.83 inches (compared to the Summit Folder’s 8.75-inch length). But it is in the same price range at $275.

What Does an Expert Think?

As noted, I am not a materials scientist, nor do I have the equipment or resources to have this Friction Forged steel lab tested to verify DiamondBlades’ claims of steel superiority.

However, I was able to contact Larrin Thomas, a steel metallurgist in Pittsburgh, PA, and the founder of the blog Knife Steel Nerds, to talk about steel grain. Thomas has a PhD in Metallurgical and Materials Engineering from the Colorado School of Mines. He offered some interesting perspectives on Friction steel.

Diamond Blades claims that its Friction Forging process creates steel grain structures that are 10x finer than those of traditional D2 steel. However, Thomas believes that it’s more likely that the steel grain structures, while still very small, aren’t quite that microscopic.

According to Thomas, “There is at least one published study on friction forging of D2 tool steel … where they found the friction forged D2 to have a grain size of 2.3 microns. This is a very fine grain size but is significantly larger than the 0.5-micron claim of DiamondBlades. The 2.3 microns measurement would likely be more reasonable.”

Thomas said that there is a small improvement in carbide size with Friction Forged steel. But he adds that powder metallurgy is much better for making the carbide size both smaller and more consistent.

“I think it is interesting and unique,” Thomas said of the Friction Forged steel from DiamondBlades. “Though, for me, I would rather use powder metallurgy steel for its superior carbide structure.”

DiamondBlade Knives Summit Folder: Who Is It For?

If you are a frequent knife user who likes larger-sized blades that you don’t have to sharpen often, DiamondBlade Knives made the Summit Folder for you. It’s a very capable knife with an extremely sharp blade that holds its edge very well.

I can’t confirm or deny that it will “outperform any other knife by 10 times” — that’s just an impossible claim to test without access to a lab. But I can say for sure the edge on this blade outlasted the other two I’ve been using and testing in the last year.

I can also tell you that it regained that edge when I put it to a whetstone (with some elbow grease). And I can confirm that I haven’t seen a single chip or bite along the Friction Forged edge despite a year of use.

Honestly, I like this knife so much I’ve been trying to wear it day-to-day. It might be overkill, though. Especially with that bulky sheath, this knife is hard to use for EDC. Although it is legal to carry in my state of Colorado, as the blade falls a hair’s width below the legal length limit. Still, I’d need a pocket clip to make daily carry realistic for me.

The point is, I like this knife so much I want to use it more than I can. I’m looking for any opportunity to cut, slice, or trim things when my Summit Folder is on me.