Cuts Like a Knife: A Basic Guide to Knife Steel

By CTD Mike published on in Blades and Knives

I’m the first to admit it—I’m not really a knife guy. I have a few knives, sure, a couple of big fixed blades and a few smaller folders, but I didn’t spend a lot of money on any of them. A while back I did a lot of research on tactical knives, and I was astounded by the range of prices on knives that look pretty darn similar. What’s the difference between a $14 Remington knife and a $165 Benchmade? Certain knives made with unusual features or exceptionally high quality craftsmanship are worth a price bump over their more ordinary counterparts. However, the one thing that consistently separates an expensive knife from a cheap knife is the type of steel used in the blade.

The high end: this Spyderco is fearsome, and so is its $160 price tag

I know we don’t live in the bronze age or iron age anymore, but what exactly is steel anyway? Steel is good old-fashioned iron combined with carbon. Adding additional metals to the combination results in alloyed steel. An example of an alloyed steel is stainless steel, which has chromium added to the iron and carbon combination in order to make the metal rust resistant. The amount of chromium in the combination is only around 13%, so it will still corrode and rust if not maintained; remember, we call it stainless steel, not rustless steel! Adding vanadium, nickel, boron, and other elements to the mix further increases the hardness of the alloy. Combining these elements in different fractions and with different methods changes the properties of the steel dramatically. If you are a newbie like me, your first thought is, “Why not just make the metal as hard as possible, so it’ll cut anything and hold its edge forever?” The answer is that hardness leads to brittleness—an imaginary knife built to be as hard as possible would shatter like glass if you dropped it on a concrete floor. On the other hand, metal that is too soft easily deforms and won’t hold an edge at all. This means the guy carefully sharpening his $30 eBay fantasy sword is really just wasting a lot of time.

One way to combine the flexibility of soft metal with the cutting edge of hard metal is by creating laminated steel. A laminated steel blade has a core of hard steel on the inside, which provides the hard cutting edge. Surrounding the entire core except for that edge is a softer steel, which shields the core when the blade is twisted or bent, preventing the blade from snapping. Ancient samurai swords were made this way, using a labor intensive welding process in which the metals were folded together as many as 16 times over the course of many days or even weeks of work. An awesome Youtube video shows one of these swords cutting a .45 ACP-round, fired from a 1911, in half! When done right, laminated steel can be spectacular.

For those of us not living in feudal Japan, here are a few common steels and some knives that use them.  420 or 4034 stainless steels are the softest and least expensive. The presence of these steels usually means the knife is mass produced and imported from China. These steels are not brittle, but they do not stay sharp for long either. Still, if you want an aggressively styled assisted-opening tactical knife but do not want to spend much more than $30, a 4034 steel Smith and Wesson M&P makes it possible. The AUS steels such as AUS-6 or AUS-8A have vanadium in them for hardness and will hold their edge longer. The Columbia River Knife and Tool company likes to use these steels in their blades. 1095 carbon steel has a high degree of carbon in it for increased hardness; the legendary Ka-Bar fighting knives are made from this steel.  VG-10 is a stainless steel with a high percentage of vanadium content, which can hold an extremely sharp edge for a long time. SOG offers several knives using this steel, but you won’t find them in the cheapie clearance bin. Sypderco makes a few knives using H1 steel which is made with nitrogen instead of carbon, making it virtually rust proof. These knives are intended for extremely hard use by people doing stuff like salt-water sea diving. Steels like H1 show what is possible with modern technology when you’re willing to pay.

Of course, there are a few knives that stand above the rest when it comes to value. Glock won’t say what steel they make their knives out of, but the $25 Glock knife will withstand torture tests that destroy knives costing four times as much. This knife is standard issue for the Austrian armed forces, whose special forces do weird things with them like splitting rocks in half on landing beaches. I’m probably never going to do anything like that, but it’s nice to know my Glock knife won’t let me down in ordinary use. On the other hand, I can’t carry that huge fixed blade in my pants pocket every day. Should I buy a cheap folding knife with a soft blade, or a more expensive folding knife with a higher quality edge? Maybe I’ll get both…

Best value? The indestructible Glock knife costs only $25.

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