Knife making is both an art and a science, and the choice of steel is crucial to the performance, durability, and sharpness of the knife. Here’s an overview of some popular types of steel used in knife making.
Knife Making Steel: Understanding Steel in Blacksmithing
Steel is the primary material used by blacksmiths. It’s a well-known fact that steel is an alloy of iron and carbon. Based on the carbon content, steels are categorized into:
- Low Carbon Steel: Contains up to 0.25% carbon.
- Medium Carbon Steel: Contains between 0.25% and 0.6% carbon.
- High Carbon Steel: Contains between 0.6% and 2% carbon.
Increasing the carbon content in steel enhances its hardness and hardenability but reduces its malleability and ductility. To improve the physical and mechanical properties of steel, various additives are introduced, such as nickel, arsenic, copper, phosphorus, sulfur, and more. The content of these additives is strictly controlled because exceeding certain thresholds can degrade the quality of the steel. It’s particularly crucial to ensure that sulfur and phosphorus contents remain low, as their minimal presence indicates higher steel quality.
Depending on their chemical composition, steels are divided into carbon steels and alloy steels. Carbon steels are further classified into:
- Ordinary Quality Steels: Suitable for blacksmithing due to their malleability, these steels contain carbon ranging from 0.1% to 0.3%. They are easily weldable and cuttable. Examples include Ст0, Ст1, and Ст2 steels. Steels Ст3-Ст6 are also satisfactory and are commonly found as wire, rods, strips, and sheets. For instance, Ст0 steel is often used for construction reinforcement, Ст1 for welding structures, and Ст2 and Ст3 for railroad spikes, bolts, nuts, and nails.
- Quality Carbon Steels: These have reduced harmful impurities, resulting in enhanced quality and mechanical properties. The best for forging are Ст10 and Ст15 steels, containing 0.10% and 0.15% carbon, respectively.
- Carbon Tool Steels: Used for making various tools. Their labels start with the letter “У”, followed by numbers indicating the carbon content in tenths of a percent. For instance, У9 steel contains 0.9% carbon. Tool steel can also be repurposed from old, unusable tools.
Alloy steels contain additives that confer specific properties. For example, nickel enhances strength and corrosion resistance, while tungsten and vanadium increase heat resistance and slow down scale formation at high temperatures. Silicon adds elasticity. Depending on the properties acquired through alloying, these steels are used in structures that must withstand significant physical, mechanical, or physicochemical loads. They’re also used to craft various tools.
- Carbon Steels:
- 1095: This is one of the most popular plain carbon steels. It’s hard, holds an edge well, but is also quite brittle. It’s prone to rust if not properly cared for.
- 1080/1084: Slightly less carbon than 1095, making it a bit tougher but not as hard. It’s a good choice for beginner knife makers.
- Tool Steels:
- O1: A popular tool steel. Holds an edge well and is relatively easy to sharpen.
- D2: More wear-resistant than O1 but can be more difficult to sharpen. It’s semi-stainless, meaning it has some resistance to rust but not as much as true stainless steels.
- A2: Offers a good balance between hardness and toughness.
- Stainless Steels:
- 440C: Once the gold standard for stainless in knives, it offers good corrosion resistance and can achieve a high hardness.
- VG-10: A high-end stainless steel that’s popular in Japanese kitchen knives. It’s known for its ability to take a very sharp edge.
- CPM-S30V and CPM-S35VN: These are premium stainless steels known for their edge retention and toughness. They’re often used in high-end pocket knives.
- High-Speed Steels:
- M2: Holds an edge very well but can be brittle. It’s not as common in knives as in industrial tools.
- Damascus Steel: This isn’t a type of steel per se, but rather a blend of two or more steels to create a patterned appearance. The performance of a Damascus blade depends on the steels used.
- Other Specialty Steels:
- CPM-3V: Known for its extreme toughness.
- CPM-M4: Offers high wear resistance and toughness.
- Elmax, M390, and CTS-204P: These are ultra-premium stainless steels known for their edge retention and corrosion resistance.
- Non-Steel Materials:
- Titanium: Sometimes used in knives for its light weight and corrosion resistance, but it’s not as hard as steel.
- Ceramic: Extremely hard and can maintain a sharp edge for a long time, but they’re also very brittle.
From colored metals, blacksmithing mainly uses copper and its alloys (brass, bronze), as well as aluminum and its alloys.
If you’re working with factory-made materials with clear labels, it’s easy to identify the steel grade. But if you’re working with recycled metal, how can you determine its grade? One method involves using a grinding wheel. The tiny metal shavings produced during grinding emit a unique spark pattern for each metal or alloy. By observing these sparks, you can identify the metal in question.
For instance, low carbon steel, with approximately 0.1-0.2% carbon, emits straw-yellow, slightly curved sparks that fan out and thicken in the middle and end. As carbon content increases, the main spark pattern remains, but more bright star-like sparks appear around the fan. High carbon steels, including tool steels, produce abundant star-like sparks.
The spark colors of carbon steels range from straw-yellow to light-yellow. Chromium steel emits long, orange-red sparks with short, thin branches and stars at the ends. Tungsten steel sparks are intermittent with small thickenings at the end.
How to identify steel grades based on their spark patterns
Here’s a basic table to help identify steel grades based on their spark patterns:
| Steel Type | Spark Description |
|---|---|
| Low Carbon Steel (e.g., 1018) | Sparks are few, short, and straight. They will have a slight fork and will not burst. The color is predominantly red due to the low carbon content. |
| Medium Carbon Steel (e.g., 1045) | Sparks are more numerous than low carbon steel, longer, and have a few more branches or forks. There’s a slight increase in the spark’s brightness. |
| High Carbon Steel (e.g., 1095) | Sparks are bright and will burst out more like fireworks. They are more branched out and have a bushy appearance. |
| High-Speed Steel (e.g., T1) | Sparks are dense, short, and have a lot of branches. They are very bright and can appear almost white. |
| Stainless Steel (e.g., 304, 316) | Sparks are sparse and short. They don’t fork out as much as carbon steels. The color can be a mix of red and orange. |
| Manganese Steel (e.g., Hadfield steel) | Produces a medium-length spark that has a slight orange color. The spark is dense and has fewer branches than high carbon steel. |
| Nickel-Chromium Steel (e.g., 4340) | The sparks are similar to medium carbon steel but may have a slightly different color or brightness due to the alloying elements. |
It’s important to note that spark testing is a qualitative method and is not 100% accurate. It’s best used as a preliminary test when the exact grade of steel is unknown.
Determining Forging Temperatures for Steel
Every material, based on its chemical composition, has a specific forging temperature, or rather, a range of temperatures. The upper limit of this range is the temperature to which the workpiece is heated in the forge before forging. The forging process continues until the workpiece cools down to the lower limit of the forging temperature range. Within this temperature range, the metal’s plasticity is sufficiently high, making it easier to work with. Equally important, the metal’s internal structure remains unaffected by the mechanical impacts of blacksmithing tools.
It’s crucial to accurately determine the heating temperature of the workpiece before starting the forging process. Overheating the metal can significantly reduce its plasticity. Extreme overheating can lead to metal burnout, causing the metal to disintegrate during forging. Conversely, forging a workpiece heated below the forging temperature can result in cracks.
Since ancient times, blacksmiths have learned to determine the temperature of forgings by their color. As metal heats up, it goes through a spectrum of colors. Initially, various temper colors appear, followed by the first hardening color. As the heating continues, all the hardening colors manifest. At maximum temperatures, the hardening color is bright white.
Below are tables that provide temperatures corresponding to various temper and hardening colors for Knife Making Steel.
Temper Colors and Corresponding Temperatures for Knife Making Steel
| Temper Color | Temperature (°C) |
|---|---|
| Pale Yellow | 210 |
| Light Yellow | 220 |
| Yellow | 230 |
| Dark Yellow | 240 |
| Brown | 255 |
| Brownish-Red | 265 |
| Purple | 285 |
| Dark Blue | 300 |
| Light Blue | 325 |
| Gray | 330 |
Hardening Colors and Corresponding Temperatures for Knife Making Steel:
| Hardening Color | Temperature (°C) |
|---|---|
| Dark Brown (visible in dark) | 530-570 |
| Brownish-Red | 580-650 |
| Dark Red | 650-730 |
| Dark Cherry-Red | 730-770 |
| Cherry-Red | 770-800 |
| Light Cherry-Red | 800-830 |
| Light Red | 830-900 |
| Orange | 900-1050 |
| Dark Yellow | 1050-1150 |
| Straw Yellow | 1150-1200 |
| Lemon | 1200-1400 |
| White (of varying brightness) | 1400 |
How to buy Knife Making Steel blanks?
If you’re looking to buy steel blanks for knife making, here’s a step-by-step guide:
- Determine the Type of Steel You Need: As mentioned in the previous answer, there are various types of steel suitable for knife making, each with its own properties. Decide on the type of steel based on the intended use of the knife and your personal preferences.
- Research Suppliers:
- Online Retailers: Websites like www.amazon.com, Jantz Supply, Texas Knifemaker’s Supply, and Knife Making are popular sources for knife making supplies, including steel blanks.
- Local Metal Suppliers: Some metal suppliers or steel mills might carry suitable steels for knife making. It’s worth checking local businesses.
- Specialty Suppliers: Some companies specialize in providing high-quality steels specifically for knife making.
- Check the Dimensions: Ensure the steel blank’s dimensions (thickness, width, and length) are suitable for the knife you intend to make.
- Consider Pre-hardened vs. Annealed Steel:
- Pre-hardened: This steel is already heat-treated and is hard. It’s more challenging to shape but will maintain its hardness during the knife-making process.
- Annealed: This steel is soft and easier to shape. After shaping the knife, you’ll need to heat-treat it to achieve the desired hardness.
- Place Your Order: Once you’ve found a suitable supplier and determined the type and dimensions of the steel you need, place your order. If ordering online, make sure to factor in shipping costs and delivery times.
Top7 Manufacturers and Suppliers of Knife Making Steel
Several manufacturers and suppliers are well-regarded in the industry. Here’s a list of some prominent ones, along with a general idea of pricing. Please note that prices can vary based on the type of steel, dimensions, and market fluctuations, so the figures provided are approximate and might change over time.
- Jantz Supply:
- One of the most popular sources for knife-making supplies in the U.S.
- Price Range: $10 – $100+ depending on the type and size of the blank.
- Texas Knifemaker’s Supply:
- Offers a wide range of knife-making materials and tools.
- Price Range: $10 – $80+ for most blanks.
- Knife Making (knifemaking.com):
- Another well-known supplier with a broad selection.
- Price Range: $8 – $100+ based on the type and size.
- Alabama Damascus Steel & Cutlery:
- Specializes in Damascus steel blanks, which tend to be pricier due to their intricate patterns and the labor involved in making them.
- Price Range: $50 – $200+ for Damascus blanks.
- USA Knife Maker:
- Offers a variety of knife-making supplies, including steel blanks.
- Price Range: $10 – $90+ for most blanks.
- Brisa (in Europe):
- A popular supplier for European knife makers.
- Price Range: €10 – €100+ depending on the type and size.
- Nordic Edge (in Europe):
- Offers a variety of knife-making materials.
- Price Range: €10 – €80+ for most blanks.
Remember, when buying knife blanks, you’re not just paying for the steel but also for the convenience of having it pre-shaped and, in some cases, pre-hardened. If you’re looking to save money and have the necessary equipment, you can also consider buying raw steel and shaping it yourself.
Lastly, always check reviews, ask for recommendations in knife-making communities, and ensure you’re buying from a reputable supplier to get the best quality for your money.