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CHAPTER 1: THE STEEL

You can go ahead and make the most beautiful knife ever, but without the proper type of steel, you could be left with a paperweight and many hours of work down the drain. If you want a knife that will stay sharp, straight, and reliable, then it is extremely important to understand what types of steels are good for knifemaking.

Damascus steel: the combination of high-carbon and nickel-bearing steels results in eye-catching patterns.

When choosing knife steel, you are looking for steel that is hard and tough. There’s a sweet spot between these two characteristics and that’s exactly where you want your steel to fall. A blade that is hard will have good edge retention and stay sharp for an extended period of time; a blade that is tough will withstand the abuse of heavy use.

Making a selection comes down to how you want your knife to perform. The steel you choose and your method of heat treatment (which I cover later on) will determine the hardness, toughness, wear resistance, corrosion resistance, and edge retention of your blade.

Steels with proper amounts of carbon are desirable to the knifemaker because the right carbon content allows the steel to be hardened. Hardening a blade provides the needed strength to survive impact and everyday use (and abuse). Using mild steel, which contains very low amounts of carbon, will result in a poorly performing blade. When using a material such as cast iron, where the carbon content is much higher than needed, you’ll again be left with a poorly performing blade.

Choosing your steel can seem overwhelming, and not just because the wrong choice may lead to complete disaster, but also because there are almost countless types of steels available.

I could write a separate book focused only on steel for the knifemaker. For this go-round, however, I’ll focus on the basics—everything you need to get started with steel. I’ll be categorizing knife steel into five groups: tool steel, high-carbon steel, stainless steel, Damascus steel, and recycled steel.

Take your time selecting steel. A bad steel choice can lead to blade failure and it’s not worth the headache. This blade was made using 80CRV2, which is a high-carbon chrome vanadium that is extremely tough.

Buying Steel

When purchasing steel from a manufacturer it will often be available in a variety of shapes and lengths. Most commonly, you’ll want to seek out flat-bar steel. This can be purchased at the desired width and thickness, saving you steps in the shaping process later on. Steel is also commonly found as round-stock or square-stock; these shapes will need to be flattened out to create a usable surface, so keep this in mind when selecting the size and shape of the steel you’re buying.

*These steels are my personal favorites for knifemaking.

Set of knives made from high-carbon steel.

High-Carbon Steel

Common in survival and outdoor knives, carbon steel has proven to be sturdy and durable. It takes an edge well and sharpens easily. The downfall is that it is more prone to rust and corrosion. In my opinion, this kind of steel is the best place to start as a new knifemaker. It usually comes with a lower price tag and, with a proper heat treatment, will hold up through a lot of use.

Common Types: 1095* 1084* 1080 1075 5160

Tool Steel

The label “tool steel” represents a wide variety of carbon and alloy steels that have a distinct hardness and edge retention ideal for making tools. I’ve made many knives from tool steel. It can be a tough and very hard material. Even prior to hardening, I’ve had troubles drilling holes in tool steel without fully annealing or softening the steel. When heat-treated properly, tool steel will hold a great edge and outperform many other steels on the market.

Common Types: D2 O1* CPM Steels A2

Stainless Steel

Famous for its resistance to corrosion, stainless steel is made up of carbon steel and chromium. Chromium is what provides this steel with its corrosion resistance. It’s common to consider this a non-rusting steel but, in less than ideal conditions and with improper care, stainless steel will absolutely rust—think of it as “stains-less.” When compared to higher carbon steel, stainless can lack toughness and edge retention. Stainless steel is commonly found in kitchen knives, folding knives, and utility knives.

Common Types: 440 440C AUS 154CM

Damascus Steel

Damascus steel is made when multiple layers of metal have been laminated or forge-welded to create one homogenous piece. Oftentimes referred to as pattern welded steel, modern Damascus steel is generally made with the combination of high-carbon steel, such as 1084, and nickel-bearing steel, such as 15N20. The combination of these steels results in eye-catching patterns that are altered though folding, twisting, and other manipulations of the steel. The completed piece is then etched in an acid such as ferric chloride, which reveals the pattern by eating away the high-carbon steel and hardly reacting with the nickel-bearing steel.

Damascus was first produced over 2,000 years ago, with origins in ancient India. There are many different categories of Damascus steel, such as San Mai, mosaic Damascus, or canister Damascus. Making your own Damascus steel can be a very complex and time-consuming process, and it’s not something I’d recommend to a beginner in the craft. It requires very accurate levels of higher forge-welding temperatures, as well as a fluxing agent to help reduce scale buildup when the billet or layers of steel are heated. This is a more advanced process that I won’t go into detail here. Damascus steel can be purchased premade from some steel and knifemaking suppliers, but it usually comes with a higher price tag.

Damascus knife made up of over fifty layers of high-carbon and nickel-bearing steel.

A billet of steel prepared to be forge-welded into a piece of Damascus.

A Damascus steel blade (left) next to an O1 tool steel blade. Both are in the final stages of polishing.

Recycled Steel

High-quality steels can be expensive. This is why most knifemakers start out in the scrapyard. You can save a lot of money scrapping for steel, but you can’t always be certain of the quality that you’re getting. I’ve picked up a few tricks that are very helpful when choosing recycled steel.

MAGNET TEST

The first thing you want to verify is that your steel is indeed steel. Some alloys such as zirconium and nickel silver may come across as steel even though they aren’t. A quick way to solve this problem is by using a magnet. If it sticks, then it’s steel.

Grinding high carbon steel will result in a much brighter display of sparks that feature more branches and veins that a mild steel would.

SPARK TEST

Now that you have a piece of steel, you’ll want to check its carbon content. If it’s the frame of your bike, I’ll tell you now that it’s probably mild steel, but if it’s the chain or the gears, you may be in luck. When looking for scrap steel, keep an eye out for tools such as files or pry bars and moving parts such as axles or springs. You can check for carbon content by using the spark test. The spark test isn’t a foolproof method, but it generally works. Steel with higher carbon content will display more forks and branches in their sparks when held to a grinder. Those with lower carbon contents will display much smaller sparks that are not as bright.

Mild steel offers a much less impressive display of sparks.

HARDNESS TEST

The final test that I like to do is a hardness test. You can do this by heating the steel up to above its nonmagnetic temperature, which is around 1420°F (771°C) for most carbon steels or until it is a yellow-orange color and then quenching it into oil. You can then try cutting into the steel with a file. If the steel has been properly hardened, the file should skate off without removing any material.

You’d be surprised at how many scrap items can be repurposed into knife blades.

I’ve seen blades made from hand files, leaf springs, lawnmower blades, railroad spikes—you name it. Using recycled steel is a way to tinker around without losing much money on material costs. It can also be a great way to “breathe new knife” into an old piece of junk!

This knife was made from an old file.

You’d be surprised at how many scrap items can be repurposed into knife blades. Lawnmower blades and hand files will both hold a great edge when heat treated properly. Rebar or railroad spikes are hit or miss. Springs or bearings are great choices for knife steel because they are designed to flex and undergo routine pressure and movements that require the steel to be accurately tempered. I also keep some mild steels on hand that are great for practicing techniques or creating jigs.