You might be wondering, isn't buying a knife way easier than making your own? While this is true, mass-produced knives lack character and uniqueness. On the other hand, forging your own knife adds personality and makes it unique.
Another benefit of knife making is that it is cheaper. With the right scrap metals, you can forge a knife that boasts high-quality and works as great as a store-bought knife. In addition, making your own knives is cheaper than buying brand new knives.
If you are ready to explore the art of knife making, this article will help you get started. You will learn the best scrap metal for knife making and where to source it. In addition, we will include tests to help you determine if the sourced scrap metal is strong and hard enough for making knives.
What Is the Best Scrap Metal for Knife Making?
Before you start forging your knife, it is important to keep in mind the desired purpose of the knife. Ideally, you need the knife to be flexible, hard and to hold a keen edge. For example, if you're making a cutting knife, you want it to be hard and strong but not as tough as it is not facing much impact.
On the other hand, blades meant to withstand impacts, such as a machete or hatchet, need to be tough and strong. Your knife's hardness, toughness, and strength will be determined by its carbon content. High carbon content keeps the iron atoms together; hence the knife will be hard and strong.
Unfortunately, too much carbon content could make your knife brittle. In turn, it will fracture on high impact. Therefore, go for scrap metal with the right carbon and alloy percentage to ensure it doesn't break or get damaged when in use.
Below are the best scrap metals to get you started.
What are the best scrap metal for knife making?
- Suspension Springs
- Leaf Springs
- Tool Steels
- Carbon Steel
- Steel Cable
- Stainless Steel
- Steel Files
- Railroad Spikes
- Saw Blades
1. Suspension Springs
Our first entry on the best scrap metals for knife making is suspension springs. These are coiled metal pieces installed between the body and wheel of a vehicle. In addition, suspension springs can be made of different materials, from titanium and steel to bronze.
Although suspension springs are coiled, you can unwrap or break a piece off the springs to use it for knife making. Additionally, suspension springs are very easy to source. Since they're often used in cars, you could find them in a garage, a suspension shop or a junkyard.
2. Leaf Springs
Leaf springs are an excellent choice for making a knife blade. They are super easy to use if you are new to the knife forging process, as they are naturally flat. This makes it relatively easy to form the metal into a knife. However, since leaf springs are made of hard steel, you need to anneal them.
Since leaf springs are similar to suspension springs but flat in shape, sourcing them is not challenging. A trip to your local junkyard or hardware store is all you will need.
3. Tool Steels
Tool steel is loved by many knife enthusiasts and for a good reason. For starters, you will often find that most tool steels are carbon steels that have added alloys. By doing so, the elements in carbon steel are enhanced, from the characteristics to the quality.
Tool steels also have high corrosion resistance. This means that although the metal is not resistant to corrosion, it will still perform effectively, unlike stainless steel.
Different types of tool steel have different characteristics. For example, A2 steel has high toughness, but you will need proper maintenance to prevent it from rusting. In addition, compared to other tool steels, it is not as hard.
D2 metal has high corrosion resistance. It is also good for high edge retention, but it falls short in hardness. Lastly, M2 metal is good for retaining the knife-edge well. However, it is quite brittle.
Metal supermarkets are a good place to source tool steel. They also cut it for you, so you get only the size you will need. Your local hardware is also a good place to check. Unfortunately, there is a chance that they may not cut the steel for you.
4. Carbon Steel
Carbon steel is also quite popular among knife enthusiasts. This type of metal boasts high hardness and strength, which you want for knife making.
It is also important that you regularly treat carbon steel. This is because it can become brittle, which then results in breakage. But, again, depending on how you treat the metal, there lies a chance that it could get too soft. This means that the knife will not properly hold a sharp edge.
Rusting is also common with carbon steel as it does not have alloying elements that protect it from rusting. For this reason, you need to ensure you take great care of the metal to prevent corrosion. Storing the blade in a sheath when not in use and avoiding leaving it in humid and moist areas are great ways to take care of the metal. Additionally, regular sharpening helps carbon steel last longer.
It is relatively easy to find carbon steel for knife making. A good place to start is looking at old cars in junkyards. You can also find carbon steel in lumberyards, where they throw away chains, bearings and chainsaw blades in usable conditions. Finally, metal depots and recycling depots will also have carbon steel, so be sure to check there too.
5. Steel Cable
Steel cable is braided steel waiting to be sourced as a knife scrap metal. The high carbon concentration makes hard and strong knives. However, you will have to take great care of the metal to prevent rusting.
If you wish to use a steel cable, you will be required to uncoil the cable then heat it to reform it. Once you have separated the steel, you can make one or more unique knives with scrap steel.
Steel cables are easy to find at a junkyard or a construction site. However, you may e able to get it at your local hardware store. If this is the case, it would be best to go for flat sheets rather than braided ones. In addition, elevator cable is a great alternative. But, unfortunately, sourcing it could be challenging.
6. Stainless Steel
Stainless steel is undoubtedly the best scrap metal for knife making. This is because it contains various alloys, like chromium, which increase the corrosion resistance. In turn, knives made of stainless steel do not deteriorate in time compared to those made of carbon steel.
Another great feature about stainless steel is that it has great edge retention. Although ferritic and martensitic stainless steel grades are used for forging knives, the best grades are either 420 or 440. In addition, other people use the austenitic 316-grade to forge knives. However, it is not as hard and does not retain the edge as well as the 420 and 440 grades.
Other stainless steel grades include the 304L grade. Unfortunately, stainless steel knives made of this grade will be very weak. However, there is also precipitation-hardening stainless steel with extremely high corrosion resistance. If you are interested in this type, go for the 17-7 PH grade.
Sourcing stainless steel is quite the breeze. Take a trip around the metal shop or hardware store and you will find the metal there. In addition, you can look at dump piles and junkyards for the metal.
7. Steel Files
If you are a knife forging beginner, we recommend starting with steel files. This is because they make small but incredibly sharp knife blades. In addition, the knife will fit perfectly into your hands.
The only challenge with using steel files is that they are hard. This means that you will need to anneal, curve the knife shape then reharden the metal, which is all not beginner-friendly processes. However, you will get a strong, durable and versatile knife that holds the edge well.
You can source steel files online on Amazon, at a hardware store or a metalworking shop.
8. Railroad Spikes
Railroad spikes are a popular knife-making choice for many enthusiasts. One of the reasons for this is that the spikes are already shaped hence easy to work with. In addition, you will only need to sharpen the end of the spike and flatten it into a blade.
The size of the railroad spike also makes it perfect for making knives. Once you have your sharpened blade, the other spike end serves as a handle that you can engrave to make it look unique.
Railroad spikes have a high carbon steel concentration. This makes them naturally strong, tough and durable enough to absorb high impact. In addition, as with using any high carbon steel scrap, you will need to take great care of your blade as it will be prone to rust.
Edge retention will also be quite challenging to maintain with railroad spikes knives.
In terms of sourcing, you may be lucky to find one or two spikes lying around in a junkyard. If not, be sure to check a dumpsite.
9. Saw Blades
You will be in for a fun but not so easy knife-forging experience with circular chainsaw blades. While you will not use the entire saw blade, you can cut a piece or more to make a few knives.
When working with saw blades, it is advisable to go for old blades rather than new ones. This is because a new blade, although sharp, will not be as strong as an old one. In addition, holding shape will be difficult and the knife will easily break.
An old saw blade will be your best friend for a strong, hard and great edge retaining knife.
Sourcing old saw blades is super easy. You could start by asking your neighbors and friends if they have any lying around in their garages. Another option would be looking around a dumpsite or a junkyard.
What Should You Look for In the Best Scrap for Knife Making?
1. What Was It Before?
One of the easiest ways to know if a scrap metal will be viable is by looking at what it was before. Steel that has been put to strain before will have a high carbon percentage to withstand pulling and pushing but will still be a low carbon scrap, just enough to avoid being brittle and breaking.
2. Size Needed
It is also essential to consider the knife size you wish to forge. This means that you will need to find metal with enough size to fit your project. In addition, while you can make different shapes from it, there is no way that you can extend the length to fit your desired size.
However, it is easier to have a bigger-sized scrap metal to cut small pieces to make knives. This is also why most scrap knives are small.
To determine their strength, toughness, and hardness, you can perform basic tests on spring steel, cast iron, and other metals. Also, if there is any serious damage or fractures on the metal, the chances are that it will not withstand the forging process.
i). Smack Test
The smack or break tests help determine if the scrap steel is usable for knife making. First, heat the scrap until it does not conduct electricity or is not magnetic. Next, quench it in oil or water to harden it.
Once the metal is cooled down, put it in a vice to tighten it. Next, hit the scrap as hard as you can using a hammer and note what happens. If the metal snaps off or breaks, it is hardenable and has a high carbon composition. In addition, it will make a great knife.
On the other hand, it is low carbon steel if the metal bends. Alternatively, if you quenched with oil, it could mean that it is a water quenching steel; hence you will need to repeat the smack test with water instead.
Scraps that bend on both tests are ideally not good for making knives as they will not hold edge well. In addition, if the hardened metal bends before breaking, its carbon content lies somewhere in the middle. You could use the scrap to make a relatively fair-quality knife.
ii). Spark Test
If you have unknown steel that you would like to identify, the spark test is a good way to do so. Technically, the sparks thrown off when you touch the metal to your grinding wheel will identify the shape and carbon content of the metal. For example, long straight sparks mean that the metal is mild steel, while short and condensed sparks characterize white cast iron.
This guide shows various scrap metal options that you can convert from raw material to a finished blade. Of course, carbon steel will be your go-to if you are looking for a strong and hard knife. However, keep in mind that you will need to take care of it.
Overall stainless steel is a great scrap for knife forging. It is strong, corrosion-resistant and has good edge retention.
It is also essential to keep in mind that making knives from scratch could be dangerous. In addition, if you are using unknown metal, there could be chances that toxic fumes will be produced. To avoid this, ensure that you know the metal type you will be working with beforehand.