Blade Shapes and Their Steel Composition
It is not humanly possible to know every fact in the universe by yourself. That is why we have spread our vast knowledge over many people, books, and other various resources. There is only one of me. This is why I’m going to zero in on a lone topic: Blade Shapes and Their Steel Composition. I am fairly versed in this subject, as knife collecting has been a long time hobby of mine. The basic outline of the metal knife has been around for more than 5000 years. Over this span of time, the shapes of the blade(s) have changed, and different steels have been used. Knives have helped and will continue to help mankind through the past, present, and future. Different blade types have been used for different tasks. To better understand the knife, is to better understand history.
The word knife comes from the ancient language of Norse. In Norse, blade means knifr. But, blades have been around much longer than a single language. In fact, blades are believed to be more than 2.5 million years old. 5 times older than spoken word. This is backed up by the finding of Oldowan tools. These tools are the oldest known tools in existence; and blades are at the heart of it. The process of making tools, say for instance, obsidian tools, is very interesting. The process is known as flint-knapping. In flintknapping, you start with a rock that is similar in shape to whatever you’re creating. For example, a flint-knapper interested in forming a knife as a finished product would pick a rock in the shape of a blade. From there, the craftsman would strike the rock with a harder material. such as another rock. Eventually, the process will yield a chipped triangle. This chipped triangle is a blade.
While flintknapping produces primitive tools, the tools are still highly applicable. Microscopes reveal that blades crafted 2.5 million ago are sharper than those today. This is because flintknapping yields a sheared edge. A sheared edge is sharper than a sharpened edge.
But, while primitive blades are sharper, they are, as the name suggests, primitive. Stone-age tools do not hold a usable edge for long. With a single glance on something harder than they are and they are rendered useless. It wasn’t until the bronze age 5000 years ago that blades that could be resharpened appeared. These new tools could be resharpened because they were made of a soft, malleable steel. When blades hit rock and bone, they didn’t shatter, they bent. Blades appearing at this time began to have the recognizable geometry that we call knives today.
Tangs also began to appear along with ricassos and new grind angles. But first, what is a tang? A tang is the back of a knife that the handle is attached to. Generally speaking, the longer and wider the tang, the less likely it is for a blade to separate from the handle.The separation of a handle from a blade destroys the knife, and is dangerous to use. If it weren’t for tangs, if you stabbed something, the blade would travel up the handle, cutting and/or severing your hand. There are full, half, partial, push, and rat-tail tangs. A full tang is the widest and longest. A half tang is wide, but short. A partial tang is long, but skinny. A rat-tail tang is similar to a partial tang, but is generally a little skinnier. A push tang is the shortest and skinniest of the bunch. While full tangs are heavier than their smaller brethren, full tangs are much stronger and are less susceptible to a fractured blade. A full tang also helps balance a knife, which is helpful in knife throwing and fighting. Personally, I prefer full tangs, as they are very useful. Because they are strong, you can use the butt of the knife to pound tent stakes, mince roots, hammer nails, and much more.
A ricasso is the flat part of the blade before the sharpening starts. In primitive times, there wasn’t much of a flat spot to hold on to if you wanted to “choke up” on the knife. Choking up on a knife gives you more precision in your cutting, as your hand is closer to the edge. This closeness helps the knife act like a natural extension of the arm. When blacksmithing brought forth hammer forging, ricassos began to show up more. In the stereotypical weapon of the bronze age, a sword, ricassos are not needed. Why you ask? A swordsman doesn’t need the carpenter-like-control when he’s swinging a massive hunk of steel through the air at his foes. However, while ricassos weren’t used for swords, they were extremely useful and will continue to be useful in smaller knives in the 6-12 inch range. It is almost impossible to find a knife these days without a ricasso. This is because ricassos are deeply seeded in the history of knife geometry.
When soft, malleable steel was first used during the bronze age, flintknapping blacksmiths realized that the rock no longer picked the angle that the edge plane was on; they could choose it for themselves. Angles of all kinds were used. From 90 degrees down, edge planes were experimented with. At first, chisel ground blades were made. Chisel ground blades have a flat side and a slope. This means that a chisel ground blade is easy to sharpen, keeps a sharp edge, and is easy to make. But, this is at the cost of edge retention. Many centuries later, better geometric shapes began to appear. Namely the “V”. The V grind is, as the name suggests, a V. The grind is double beveled, meaning that the edge has two slopes, instead of one. The angles are split between the two slopes, creating a more obtuse edge. An obtuse edge keeps a sharp edge longer, and is very easy to sharpen, but this comes at the price of peak sharpness. Peak sharpness is how “sharp” a blade can get. For instance, a splitting maul has a very obtuse angle. This blade (axe) would not be very good at shaving with, but a razor with an acute edge excels at this task because of its smaller angle. However, the maul with its obtuse edge will hold that edge more consistently for a longer period of use. The sharper, acute edge will not. Modern day axes and machetes keep their angles between 35-45 degrees. Pocket knives and small fixed blades keep their angles between 20-35 degrees. Personally, I prefer an 22.5 degree angle. This creates a very sharp edge.
Fast forward a few hundred years. New changes have happened to the knives. There are better steels, bellies, recurves, and blades are now stronger. The knives are stronger because of improved blacksmithing techniques that make the atoms of the steel line up better to create a solid piece of blade. Heat treating begins to be more popular at this time. Instead of casting knives like ingots, knives are forged with hammers in a process called hammer forging. Hammer forging goes hand in hand with heat treating. First a steel bar gets red hot in a furnace. The steel is more malleable when its hot. A hammer or cold chisel is used to cut and shape the blade. The blade is dunked in ice cold water to realign the molecules of steel into a tighter weave. This process is done multiple times to create a tempered blade. A tempered blade is not as brittle as one cast from an ingot and sharpened.
A belly is the convexly curving part of a knife. It can be at the tip, or in multiple places on the knife. Bellies make it easier to slice material. Slicing is better than hacking because less force is wasted through unnecessary movements like raising your axe over your head like Paul Bunyon to cut vegetables. Simply add some belly and slice away. A recurve is the concavely curving part of the knife. It is most always near the handle, or in the middle of the blade. Recurves help when hacking is absolutely necessary, like in battle. The recurved part of a knife is sharper than the belly. This added sharpness helps the blade hack through medium like bone and flesh easier. I prefer a knife with lots of belly and minimal to no recurve.
The stage set is of the 18th century. America is young, and is full of young migrant workers. Because they’re young and hardworking, they find that day to day, they keep losing grip of their folding knives. That’s right, FOLDING. In the past fixed blades were used because no-one could create the tight tolerances needed for folders. It wasn’t until the last thousand or so years that technology got to the point to where folders could be made. Anyway, workers dropped their knives often, so two countermeasures to this problem were launched: jimping and lanyard holes.
Jimping is the micro grooves cut into the spines of many modern folders for added hand traction on the blade. Lanyard holes were simply holes drilled through the knife that allowed a string to pass through. This string could be attached to your wrist, so that if the jimping didn’t give you adequate traction, and you dropped your knife, the knife would still be attached to your body, and you wouldn’t lose it. At this time, it is also notable to mention that knife steel experienced a leap in technology. This is partly due to the industrial revolution that caused a spike in steel production. Because more steel was made, more experiments were done with it. Basic carbon steels recognized today emerged from the fiery hell of molten 18th century steel.
A couple of centuries later in the 20th century, knife steel began to be a big deal. Marketing in America was a big deal. You had to sell your product to another person so that you could support yourself and your family. If you didn’t have a good product, you didn’t get paid, and as a result, you and your family went hungry. In the past, old files and leaf suspensions from cars were heavily used in the cutlery industry. It was fairly common to be cutting your steak with a knife that was made days ago from springs that were on a wrecked car. Businessmen realized that these springs and files had potential to become sharper and hold that edge for longer. So, they recruited a bunch of scientists to make cutlery steel better. Steel companies like Crucible Industries boomed. All kinds of new steels were made; the newer better than the last. Without realizing it, America had just created a battle with Japan that has not ceased to end to this day. The Americans and Japanese have fought for over 150 years on who can create a better tool steel. Both sides realized that if they could create, say, a sharper drill bit, production costs could be cut nationwide. Literally.
This is where we end. The present day. Supersteels of the 21st century are prevalent in many modern folders and fixed blades. Stainless steels have overtaken the venerable carbon steels of the past. But, what is a stainless steel? As the name suggests, a stainless steel is a steel that, well, stains less than a carbon blade. What I’m talking about is rust. The carbon blades of the past required maintenance. If you didn’t want a rusty knife, you had to oil it at the end of the day. Carbon knives exposed to salt water on ships quickly degraded and had to be replaced often. Stainless sounds good on paper, but it comes at a price. Toughness. A simple carbon knife can actually cut through its softer, stainless counterpart.
If you don’t believe me, take that old file in your garage and go ham on a knife. You can saw right through it! Stainless steel is not very tough, but it’s maintenance free. Kinda. While you don’t have to oil the blade up as often, stainless steels can pit, which is worse than the surface rust of carbon blades. Pits dig into the metal, compromising its structural integrity. Not that important to a cook, but it may be a matter of life and death if you were, say, trapped in a burning car, and the jaws of life that are to save you, snap because they were pitted. This is a very extreme example of what pitting can do. In fact, I doubt that the average consumer will ever notice pitting on their blades. Steels are just that good these days. But, there are a large number of people who can’t stand the stainless crowd. They have good reason too. Carbon blades can get sharper and hold that sharper edge for a much longer time that stainless steels. But, as technology gets better, so will stainless steels. Personally, I prefer stainless steels because I like my knives to be rust free and stay pretty. Rust is a serious issue if you have more knives than you know what to do with.
Knives in my opinion, are the most useful invention in the history of mankind. If it weren’t for knives, everything around you (manmade) wouldn’t exist. Think about it. The clothes on your back had to be cut somehow. The roof you’re under had to be cut and shaped. The car you drive, and its’ million odd nuts and bolts had to be machined somehow. How were those machines made? On a lathe. With a cutting tool. How was the lathe made? With another cutting tool. If you don’t think that knives are useful, try making a Boeing 747 with your fingernails. Face it, knives are pretty darn useful. And now that you know more about them, perhaps you’ll be a better consumer. And maybe, you’ll end up being a collector like me.