Make Your Own Bush Knife (part 1)
This article is intended to guide the home forging enthusiast in setting up a forging shop to make knives. It is excerpted from my book on knifemaking, which was published in 2020 by Fox Chapel Publishing. Part I will take you through setting up your home forge; blade design and material selection; and making a simple forge using a propane torch as a fuel source.
The knife is one of humankind’s first tools. The first knives were made about 2.5 million years ago by battering sharp flakes from stone, oftentimes used with a wooden or bone handle. About 10,000 years ago humans figured out how to make knives from copper; move forward 5,000 years and blades began to be made of bronze.
On the heels of the Bronze Age came the Iron Age. People throughout Europe, Asia and Africa began making blades from iron between 1200 BC and 600 BC, depending on the region. In modern times, we have now developed extremely tough, durable and hardened steels that are far superior to any blade material used in antiquity.
Some people who work in the forging industry desire to use their professional knowledge in a more creative way. Some are drawn to forming blades or, more specifically, to making knives. To be clear, I don’t have umpteen years of experience, and I will always consider myself a student to this craft. I feel that I’ve finally made it over the initial stress-hump of knifemaking, however, and it’s my duty to help you do the same.
So welcome to the world of knifemaking: a rabbit hole of tools, techniques, frustration, finger slices, freak-outs, passion and pride.
My advice to novices is to challenge yourself in small increments. If you cannonball into this craft, you may never make it out alive. If you take your time and learn from every mistake, knifemaking can become a rewarding and, at times, meditative craft.
First and foremost, personal safety is critical in any metalworking operation. Eye, hearing and hand protection are a must, as is skin protection from head to toe via an assortment of protective goods and clothing. Overall shop safety is also important, so make sure you have adequate ventilation, dust collection, fire protection and other equipment as part of your workspace.
On a smaller scale, all the best safety practices you know from work should be your guide in setting up and working in your home shop.
The Right Tools
For the beginning knifemaker I have narrowed things down to create a budget-friendly and modest group of 10 tools that will get anybody started making knives. You can upgrade as you go along, but here’s what you need to get started:
- Firebrick forge
- Quenching container and medium (Figure 1)
- Tempering oven
- Sharpening stone (Figure 2)
- Community – fellow knifemakers
There is, of course, much more to say about each of these tools, which space doesn’t allow here. As you progress in the craft, you may wish to add other tools such as an angle grinder, farrier-style anvil, band saw, drill press and other items. For many, however, the belt grinder is the ultimate tool for the knifemaker.
When choosing knife steel, you are looking for steel that is hard and tough. The steel you choose and your method of heat treatment will determine the hardness, toughness, wear resistance, corrosion resistance and edge retention of your blade.
In steel selection, there is a sweet spot between steel hardness and toughness, which is where you want your steel to fall. 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).
When purchasing steel, you will most commonly want to seek out flat-bar steel, which can be purchased at the desired width and thickness, saving you steps in the shaping process later. Here are the best knifemaking steels to consider:
- High-carbon steel – sturdy and durable; takes an edge well and sharpens easily; more prone to rust and corrosion; a good steel for your first blades
- Tool steel – ideal for hardness and edge retention; can be difficult to work with without annealing; makes a great blade when heat treated properly
- Stainless steel – made of carbon steel and chromium (which provides corrosion resistance); commonly found in kitchen, folding and utility knives
- Damascus steel – Modern Damascus steel is generally made with a combination of high-carbon steel and nickel-bearing steel. The combination of these steels results in eye-catching patterns altered through folding, twisting and other manipulations (Figure 3). The completed piece is etched to reveal a pattern by eating away the high-carbon steel and hardly reacting with the nickel-bearing steel.
- Recycled steel – Many knifemakers start out in the scrapyard due to cost. However, you can’t always be certain of what you are getting. There are some tricks to use when selecting scrapyard steel, so do your research before buying.
Before you even pick up your tools, I recommend coming up with a design for your knife (Figure 4). This is completely up to you, but you should consider the tasks for which it will be used before proceeding. If you want to carve wood, for example, a knife with a shorter blade would be easier to control. Knives used for skinning game or chopping wood would have blades shaped differently.
Another thing you need to consider is the actual thickness of the steel. Some will say “the thicker the steel, the stronger the knife,” and while that may be true in some sense, there’s a fine line between a usable knife and a pry bar.
Selecting a Fuel
A forge is any device used to burn fuel and retain heat. It can be as simple as a few firebricks and a fuel source. Some of the most common fuels are propane gas or solid fuels such as coke, coal or charcoal.
Propane is my fuel of choice. It is an easily accessible fuel that burns clean and is safer in the sense that it can be turned off immediately with a valve, unlike the solid fuels.
Using solid fuels requires an air supply to burn properly, usually in the form of a bellows. Coke burns cleaner and hotter than coal, but it requires more airflow to stay lit. Traditional coal burns more evenly than coke but is dirtier to run and leaves a residue in the forge called “clinker” that must be cleaned out after every session. Charcoal is the most expensive fuel because it burns faster. Use hardwood or lump charcoal, not commercial charcoal briquettes.
Making a Simple Forge
To get started, you will need to make a simple forge constructed from high-heat firebricks and a blowtorch. Standard firebricks are available at 4.5 x 9.0 inches and in thicknesses of 1.25 or 1.5 inches. The thicker the brick, the more heat it will retain. Here are five steps to make your firebrick forge.
- Create your brick forge on a safe, stable surface. Avoid placing it on a wooden workbench. Instead, consider creating a stand using metal supports or cinder blocks (Figure 5).
- Stack firebricks to create a tunnel inside of which the heat will be focused and the steel will be placed. The number of bricks used will determine the size of the forge. Insulating the walls of the forge with multiple bricks is a good way to retain more heat (Figure 6).
- A simple way to improve the forge’s efficiency is to make a door or wall to keep heat from escaping. Making it removable gives you the option of heating longer lengths of steel. You can also close the forge off when working on small knives of steel that fit inside the forge.
- A hole can be drilled into one of the walls to accept the nozzle of the blowtorch. Place the nozzle into the hole and allow the body of the torch to rest alongside the forge. Creating curved interior walls using high-heat cement or by carving the brick will allow the flame to circulate and provide a better heat.
- It will take a couple of minutes for the forge to reach a proper temperature. A smaller opening will allow it to heat up faster.
As you advance in the craft, there are many upgraded techniques and home-forge designs available.
You are now ready to heat a piece of steel that will become your first blade.
What we have covered here is but a simple summary of how to get started, with an emphasis on the metalworking aspects of the project. In my book, Making Your Own Bush Knife, there are many additional illustrations, details and tips on how to succeed.
In the second and final part of this article we will cover how to forge the blade, anneal the steel, create a cutting edge, temper and quench the blade and finish the knife.
This article has been excerpted by permission from Making Your Own Bush Knife: A Beginner’s Guide for the Backyard Knifemaker, by Bradley Richardson. The 184-page book from Fox Chapel Publishing (Lancaster, Pa.) is full of additional helpful tips and illustrations to help guide you through the knifemaking process. Author Bradley Richardson is an outdoorsman and master knifemaker who founded Timberlee Tool & Trade in Traverse City, Mich. Questions should be addressed to https://timberlee.com. For additional information about the book, please visit https://www.foxchapelpublishing.com/making-your-own-bush-knife.html.