Ever wanted to know how to make a knife? You’re in luck, my friend. I’ve written this update just for you. Before you jump right in, if you haven’t already decided on what type of steel and handle material you want to use, you might want to go check out my About TriStar Knives page where I discuss the types of steel and handle material I use and recommend to my clients. If you’re interested in a new EDC blade or something a little more formal, contact TriStar Knives to discuss your knife build.
KNIFEMAKING CAN BE EXTREMELY DANGEROUS. ALWAYS BE SURE TO WEAR PERSONAL PROTECTIVE EQUIPMENT AND OPERATE ALL MACHINERY OR TOOLS AS INTENDED AND INDICATED IN YOUR OWNER’S MANUAL.
After you’ve drawn the knife onto a piece paper, trace it onto a thin piece of plywood. Cut the plywood out for use as a stencil. You can do this with several different types of saws, but a jigsaw will likely give you the best results. After you’ve cut the stencil, trace the outline of your knife onto the steel you’ll be using for your knife. Be sure to keep your stencil so that you can make more knives from it if you decide you want to make multiple knives with that same design.
This is where the rubber meets the road, gents. Time to embrace your machismo and shred some metal! Personally, I’m a big Tool fan, but I digress. I use a workbench-mounted bandsaw to cut the steel I’m working with, but if you’ve got the strength and the endurance, you could get away with using a hacksaw. Be sure to cut on the outside edge of your markings and not right on the line, or inside of the line. It’s always better to have too much than not enough. You can always grind it down later if it’s too big, but if it’s too small… well, I guess you could tell her it’s not the size of the knife in the fight, but the size of the fight in the knife? (Your knife will be too small.)
At this point you should have the rough outline of your knife cut. Now let’s prep it for beveling.
Let’s assume that the steel you’re working is 4mm thick. This is thick enough for you to use a brightly colored paint marker and paint the cutting edge that you plan to bevel.
Now, lay the steel flat on your work surface and grab a 4mm drill bit from your toolbox. Set the drill bit down flat next to it with the point facing the steel. The drill bit and the piece of steel are the same thickness. Notice how the tip of the drill bit lines up perfectly with the middle of your steel? We’re going to use that to our advantage. Scrape the tip along the area that will be your cutting surface. The tip of the drill bit will scrape a line exactly in the middle of your steel so that you can bevel your cutting edge evenly on both sides and have them meet in the middle.
If you’re working with steel of a different thickness, use a drill bit that matches the thickness of your steel to do this.
Before you get started, you’re going to want to make a simple jig out of a block of wood, and a bolt. Yep. That’s all you really need. There are fancier jigs out there, but this one will work just fine. Divide the block roughly into thirds and drill a hole in it near the line that separates the first and second section. Your hole should be big enough to slide the bolt into.
Now, clamp the steel to the far side of your jig (the opposite side of the bolt). Face the cutting edge that you want to bevel up. When you set it back down, you’ll see that the jig sits at a slight angle because of the bolt head at the bottom that touches your working surface. This will help you to keep a constant angle on the knife. It also serves as something to grip onto while you’re beveling the knife.
Grip the jig to control the movement of the steel against the belt sander. Use one, careful and continuous motion, starting from the rear of the cutting edge and moving in the direction of the tip. Repeat this as necessary until you’re about .5mm away from the center line that you scraped with your drill bit. You’re just putting the bevel on. We’re not ready for that sharp knife edge just yet.
After you get done with the first side of the knife, unclamp it from your jig, flip it around and clamp it back on. Now bevel the other side.
Next, you’re going to want to drill holes in the tang (hilt) of the blade. This is so that you can affix the handle material to it with with pins and epoxy, or bolts, later on. You can accomplish this with a cordless drill and a metal drill bit. If you have a drill press, that’s probably your best option. Before drilling, mark the spot you want to drill into with a center punch. Hammer to form a divot that the drill bit can rest in as it starts the hole.
Now that we have the bevel done and the holes drilled, it’s time to give the blade a nice finish before heat treating it. You’re going to want to sand the entire blade with sandpaper. Start out with a rough grit and slowly work your way up to 1200 grit. You want to remove any scratches or uneven surface on the steel. Your goal is to come out with a smooth finish over the entire piece of steel. This is going to take a while, but this is a marathon, not a race. The better the pre-treat finish, the better your knife will fit with your grip and your final finish will be much easier. Don’t be afraid to go through sandpaper like it’s going out of style. You won’t get much actual sanding done if your sandpaper is clogged.
Now that you’ve given your blade a nice pre-treat finish, it’s time to heat treat it. Every type of steel performs best at different ranges of the Rockwell Scale and is assigned an HRC range on the Hardness C-Scale. Steel used for quality knife blades have an HRC range of 55–66 HRC. The higher the HRC rating, the tougher the steel is – but the more brittle it is too.
“Heat treat” covers quite a few things.
Thermocycling is when you raise the temperature of the steel past “critical temp”, then allow to cool to black in still air. Cycle it again at about 150° below the previous temp, and then cool to black in still air. Then a final time around 300° below the first temp, and then cooled to black in still air. This process refines the grain structure of the steel in order to optimize it’s final structure when hardened. Each steel calls for it’s own specific temperatures.
You raise the steel to the manufacturer’s specific temperature, then allow it to “soak” for the required amount of time. This allows for the proper reaction of the different alloys to happen. After the necessary soak, the hot steel is quenched in the appropriate oil. The oil will cool the steel at the correct rate necessary to harden the steel. If done correctly, the steel should have hardened to the highest HRC the manufacturer intended it to be capable of, typically 65+ HRC. This is too hard and brittle for a knife. It will be extremely hard to sharpen and would like break if dropped or stressed too much.
Tempering is done after hardening the steel. The steel needs to be heated to a specific temperature in order to lower the HRC to a usable hardness. Each steel will differ. The type of intended use will also be a determining factor to specific final hardness chosen. This is the process of heat treatment for the majority of high carbon steels.
Personally, I prefer working with W2 Steel, for reasons that I talk about on the About TriStar Knives page but it is reserved for the more expensive knives.
All of that heat on your blade has likely resulted in a layer of steel that has been stripped of its carbon. You’ll need to grind that layer off of your blade to reach the hardened steel underneath it. You can accomplish this with a file but a belt grinder does it much quicker.
Now that you have a piece of hardened steel in the shape of a knife, it’s time to finish the blade. Depending on the finish you’re looking to achieve, you’ll have varying degrees of work ahead of you. The type of finish you decide on will likely be influenced by the type of steel you’re working with. Finishes include: hand sand, stone wash, or satin finish. Don’t opt for a mirror finish unless you plan to mount the knife to a wall and never use it.
The goal of finishing is to completely remove all scratches from the knife. As mentioned earlier, you will go through a lot of sandpaper so don’t trade your time for the few pennies you’ll save trying to get maximum use out of each strip of sandpaper.
Start out with rough, low grit sandpaper and work your way up to the higher grit. Don’t move up to the higher grit sandpaper too quickly. You want to get the scratches out with the rough, low grit sandpaper. It will become more and more difficult to remove the scratches as you work your way up to higher grit sandpaper.
If you decide to go with a stonewash finish, acid etching is also an option. This helps to give the blade an aged look. I talked about stone washing in an earlier update, New Stonewash Tumbler!
Now it’s time to get to work on crafting your knife handle. The material you decide to work with is up to you, but some common handle materials are wood, firehose & epoxy, and fabric, burlap, or canvas micarta.
Whatever you decide, you’ll need to take the knife and place it on your handle material. Now trace the tang (the steel handle area) onto your handle material. You’re going to need to do this twice, because you’ll have handle material on both sides of your tang. After you’ve traced the outline, go ahead and cut the handle material. Rough fit it to your blade with pins and epoxy, or small hardware with a tapped thread in the steel or brass insert.
After you have the handle rough fitted, and have seen it all come together, you should get a better idea on how you want the finished handle to look. Remove the excess handle material with a saw or belt grinder. If working with wood, you can continue to further shape the handle material with a file or rasp. When the material is nearly even with the tang, go ahead and switch to using sandpaper. Like blade finishing, you’ll want to start with coarse sandpaper and work your way up to a fine grit.
Once you have the handle shaped and finished to your liking, it’s time to apply either the wood oil or the epoxy coating, depending on the handle material you chose to use.
Congratulations! Your knife is nearly complete! All that remains is sharpening the blade to a razor-like edge, which can be done with anything from a sharpening stone to your belt grinder. If you choose to use the belt grinder, be careful not to damage your newly finished handle and be sure to use the jig you created in step four.