How To Forge A Knife For Beginners
There’s something special about making your own tools, and knives are no exception. Whether you plan to craft daggers to throw for fun, make an outdoor knife for your workshop, or want a custom addition to your cutlery set, forging a knife lets you do all of that – and more.
This guide is meant as a very high level overview of the different parts of the process. I'll link out to detail guides along the way where you can dig deeper into any particular part of the process like quenching or sharpening. But this guide will give you all the pieces you need to know to get out there and hammer out your first knife.
But why should you make your own knife instead of buying one of the millions of options there are on the market? To start, in many cases it is cheaper to make your own knife because scrap can be melted to be reformed into a knife, which essentially lowers the cost to just your time.
Additionally, unless you plan to pay a ton for a custom knife from a knifemaker, you won’t have the same level of customization or story behind the blade – which is one of the coolest parts of blade forging.
If you feel like you now need your own knife (or knives.), you’re in the right place. The following guide will walk you through your first knife forging, helping you prepare accordingly and forge the best knife possible from start to finish.
Choosing Your Metal
The first and likely most important decision you will have to make before forging is choosing your metal. There are a variety of different kinds of metals out there, however steel’s combination of hardness, strength, and ability to hold an edge makes it the ideal choice. The type of steel, however, can vary as well.
If you’re feeling thrifty (or happen to live near a junk yard), you can reuse other pieces of steel by breaking or cutting a piece off and forging the knife from that. Some common scrap you may find includes railroad spikes, coil springs, or leaf spring steel like you would find in a car’s suspension. They are good options because they are made of quality steel (primarily due to the wear put on them regularly) that – when uncoiled or forged – holds an edge well for a knife and hardens well.
If you’re looking for something a bit more scientifically precise or higher quality, you can buy metal bars to craft your knife with. They come in multiple types, each with their pros and cons as well as their own individual grades that explain the chemical makeup of the metal, so you can know precisely how to use it.
Carbon steel is just what you’d expect – steel infused with carbon to add strength and hardness while losing some corrosion resistance. It is best for knives that will be subjected to impacts rather than relying on sharpness because it can lose some edge in favor of hardness. C1045 is an example of a hard carbon steel that is commonly used for knife forging, but there are plenty to choose from.
Tool steel is very similar to carbon steel, but contains additional alloys that make it more resistant to corrosion so it can be used in more situations (like for many outdoor tools). Tool steel is strong, corrosion-resistant, and can hold an edge well. However, depending on the grade of the metal it will be better at certain aspects of forging. For example, A2 tool steel is tough but more prone to rust while D2 offers better corrosion resistance and a sharper edge, but loses some toughness so it is best for low-impact.
While primarily seen in kitchen appliances and silverware, stainless steel can also be used for knife forging. It has chromium and other alloys infused that provides a boost to corrosion resistance, but they suffer when it comes to hardness and edge sharpness. However, some higher-carbon grades like 440 can be used for knife making while still standing up to the duties of a knife.
Choosing Your Fuel
After choosing your forging steel, the next decision will have to be the fuel source for your forge. Depending on your specific forging setup, fuel availability, and location, there is likely an ideal choice for you to use – either propane, coal, or charcoal.
Clean, readily available, and burns incredibly hot. With just a simple propane torch you can build yourself in an afternoon, you could directly heat metal to the point of it becoming workable. This is inefficient for forging larger pieces of course, but the same idea applies to your forge. You can also buy a forge with an integrated propane heat source for an even easier setup for a beginner.
Very hot-burning fuel source that fits into many forges easily, but may smoke you out of your workshop without proper ventilation. While an effective fuel source, the smoke produced is thick, which may alert the local authorities of a potential fire and earn you a hefty fine. For this reason (and pollution overall), coal may be illegal for you to use so check local laws before you decide to smoke up.
One of the more affordable fuel source you can use, but won’t work for everyone. Charcoal can be made on your own by burning wood, so it is very easy to get. However, even incredibly efficient forges can struggle to reach and maintain the temperatures needed to forge steel. If your only option is charcoal, it doesn’t hurt to give it a try at the beginning but be warned that you may not have the best experience.
What Tools You’ll Need
Once you’ve decided on your fuel and metal choices, the next thing you’ll need is a forge that works with your fuel of choice. If you go with propane, you can find some prebuilt forges that simply need to be fueled with a propane tank.
Alternatively, if you feel like doing it yourself a forge can be built with any of the three fuel types working just fine. You simply need air flow so that the heat can be maintained, enough room to heat your knife, and that’s it.
After your forge, you’ll need a forging hammer and a forging table or anvil that you can use to pound out the metal. It needs to be heatproof so that the extremely hot metals don’t burn a hole or set it on fire, and the hammer needs to be heavy and strong enough to stand up to the steel.
Finally, an oven or brick box is needed to temper the steel after it has been forged and shaped.
I have a guide to the gear you need when starting out if you need more detail check it out here.
The Forging Process
To get started, you’ll need to get the steel up to temperature so that it can be worked. If you have a forge that includes a thermostat for heat, you’ll want to set it to around 2,200°F or use a color guide to determine the steel’s temperature.
Once the steel is malleable, transfer it to your “pounding area” so that it can be hammered out to begin forming the blade. As you hammer on one side to develop an edge, be sure to leave a few inches for the tang so that it’s easier to handle, and flip the blade over so that it doesn’t warp towards one side.
Once you’ve formed a basic knife shape, it will need to anneal before you can further refine it. Annealing softens the metal so that shaping is easier, and you can get a more genuine knife look. You can do this by heating the blade until it is red and letting it air cool 2-3 times.
After annealing you can file it so that it begins to look polished before sending it back into the forge to begin quenching. Quenching involves heating the metal to red-hot temperatures and then quickly cooling it by dipping it in water, oil, or other substances that will reduce the temperature quickly and allow it to harden by locking the molecules in place. Once submerged tip-first, stir the blade so that it can cool evenly, surrounded by different water or oil that isn’t already heated.
One you’ve got a hard blade, it’s time to temper it so that the blade is not too brittle to use. This slight softening of the steel will bring it from all the way towards hard to closer to the middle where it is most effective as a knife. You can do this by heating it in the oven at 300°F for 2 hours, then cool it with water. Now you have a knife!
After you’ve forged, annealed, and tempered the blade, it’s time to put the finishing touches on so that it can be wielded and cut through whatever you come up against.
The blade needs a handle in place of the tang you left when forging. You have a variety of choices on how to handle your knife, but a common approach is to drill holes and mount wooden or rubber handle grips to the tang. If you don’t have access to a drill, you can handle it with rope, rubber, wood, or anything else that would make for a solid grip when using your knife. Just wrap it around the tang and secure it for grip.
You’ll also want to sharpen the blade on a file and then a whetstone in order to improve its ability to cut. This is especially important for blades with lesser blade retention because they can dull easily and become less useful.
If you’ve ever felt like forging your own knife but didn’t know where to start, you’ve hopefully learned enough from this piece to give it a try. Remember that working with anything this hot can be dangerous, so it’s important to know what you’re doing before you jump into it. However, once you get the hang of it, knife forging can be a fun and relaxing way to pass the time or make something special. Just don’t get discouraged if you break a blade or 2. It happens to everyone.
-THE STAY AT HOME DAD