How To Make a Knife From an Old Saw Blade

How To Make a Knife From an Old Saw Blade

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Survival is a huge branch of out-of-the box thinking. In some situations you can use the blade from an old saw to create a knife.

The “can you make a knife out of a saw blade” is the process of making a knife from an old saw blade. It can be done with just a few simple steps.

Homemade knife with leather sheath from saw blade.

On a lot of levels, making a knife is a fulfilling undertaking. You’re making a basic tool – one of the earliest tools ever built — and you’ll say to yourself, “Wow, I made this with my own hands every time I take it up.” You’ll be able to customize the form of the knife to meet your exact demands since you’ll be producing it yourself. The blade is the most difficult component of creating a knife. It’s fantastic if you have a forge and can get your hands on some nice tool steel. If you don’t have any, you can still build a knife by repurposing an ancient Appalachian method. That’s exactly what we’re going to accomplish with this project.

The majority of old saw blades are constructed of high-quality steel. They’re plentiful at swap meetings, garage sales, and rummage sales, among other places. The major benefit of utilizing an old saw is that you don’t have to perform any metallurgy. You don’t need to treat the steel to make it a decent knife since it’s already the correct hardness for keeping an edge. However, saw-cut blanks may be a touch too flexible at times, but you can work around (or with) this.

This knife’s steel isn’t going to be super-hard. If you attempt to cut through wood, slice cardboard, or use your knife as a screwdriver, your knife will rapidly lose its edge. Softer steel, on the other hand, may be sharpened back to a razor-sharp edge with a few strokes of a sharpening stone. I like softer steel because I enjoy a sharp edge, and I always have a little sharpening stone with me. Your knife is sharp enough if you can shave your arm hair with it.

A knife may come in a variety of shapes and designs. In this project, we’ll create a full-tang knife, which means the blade extends the whole length of the knife into the handgrip. Only a portion of a partial tang extends into the handle. In my view, the simplest way to begin producing knives is with a full-tang knife. It also results in a robust, durable knife with a lower risk of breaking at the handle. Knife diagram full tang with handles and pins.

If you treat your knife with respect, it will serve you well.

List of Materials

  • blade from an old saw
  • Manila file folder made of thin cardboard
  • Pencil
  • Scissors
  • Soapstone or chalk
  • chisel (cold)
  • To push the chisel, use a hammer.
  • Underneath your work, a sturdy metal plate.
  • Metal filing cabinets (coarse and fine)
  • Brush made of wire
  • Steel wool, coarse (00)
  • Lightly scented oil (3-in-1 or gun oil)
  • Acetone
  • rags made of cloth
  • Vise
  • C-clamps
  • Handle scales made of hardwood (oak, maple, cherry, etc.)
  • If you’re making your own scales, use a handsaw (preferably a Japanese pull saw).
  • Epoxy in two halves (slow-cure)
  • Brass rod, 3/16″
  • Drilling power
  • 3/16″ metal drill bit with a sharp point
  • Hammer with a ball-pein pattern
  • Tape for ducts
  • Patternmaker’s rasp or 4-in-hand
  • Sandpaper is a kind of sandpaper (80 and 150-grit)
  • Scraper for cabinets (optional)
  • Some kind of sharpening mechanism
  • Ear plugs or earmuffs for hearing protection

How to Create a Knife

Step 1: Get your pattern ready.

Patter for homemade knife on paper.

 

It’s your knife; it’s your design! You may either trace an existing knife onto the cardboard or create your own. In this example, I’m creating my own design based on an antique knife used by fur traders. Make sure your curves are consistent and, more importantly, attractive by using a French curve. It’s a universal fact that a tool or knife with a nice form is an excellent tool or knife. When you’ve reached the point where you’re satisfied with your form, cut it out using scissors. I didn’t add a bolster or fingerguard in my knife design, as seen in the figure above.

Step 2: Print your design on metal material.

Homemade knife patter on old saw blade.

Trace your design onto the old saw blade with a piece of chalk or soapstone. It doesn’t have to be flawless since you’ll be utilizing your eyes and filing away any faults as you go.

Step 3: Score your blade’s outline.

Cutting area marked for knife.

Put on your hearing protection and a thick piece of metal plate beneath your metal stock before beginning this stage. If you have an anvil, don’t use it to work on since you’ll be putting hardened steel on hardened steel. Something has to give, and you don’t want it to be the chisel breaking off and embedding itself somewhere in your body.

Take a deep breath and give it a big whack with your chisel, aligning it with your chalk line. It may not cut all the way through the blade, but the score it leaves is sufficient for the time being. As you make your way around the outline, overlap the chisel marks to create a single continuous line rather than a series of dashes. Please take your time.

Step 4: Get the blade out.

Bust out the blade. Creating a sheer is what breaks the metal. I do this by placing the metal over the edge of an anvil and striking it with a hammer as close the scored line and the anvil as I can. If you don’t have an anvil, put your saw blade in a vise and tap the blade as close to the cut line as you can. If you did the chisel work well your knife blade should pop right out of the metal.

The metal is broken by creating a sheer. This is accomplished by laying the metal over the edge of an anvil and hitting it with a hammer as near to the scored line as possible. Put your saw blade in a vice and tap it as near to the cut line as possible if you don’t have an anvil. Your knife blade should burst straight out of the metal if you done your chisel job correctly.

Step 5: Shape the blade using a file.

Vintage piece of Mattel.

Because the chisel doesn’t leave the best edge, you’ll need to file the piece. It’s vital to understand that sheet metal is resonant (which is why people use violin bows to play hand saws). Filing a sheet of metal produces a very torturous sound. Reduce this by gripping the blade as near to the vice as possible and wearing hearing protection.

Note: Don’t try to sharpen your knife just yet. The blade’s edge should be perpendicular to the sides. Look for a thin line that runs the length of the blade. That means you’re ready to go on to the next phase.

 

Step 6: Get the handle going.

Start the handle. We’re making a full-tang knife, which means the blade edge will be visible all the way around the handle. We’ll do this by adding a scale of wood to each side of the handle. (A scale is a flat piece of wood, bone, or some other material that will create the handle.) You can purchase pre-made scales or make your own. In this instance I’m making my own scales out of a few slats of oak trim I had laying around. Trace the outline of your blade on to your wood stock two times to create the shape of two scales. Then cut them out.

The blade edge will be visible all the way around the handle since we’re building a full-tang knife. We’ll do this by attaching a wooden scale on either side of the handle. (The handle will be made of a scale, which is a flat piece of wood, bone, or other material.) You may buy scales already manufactured or create your own. In this case, I’m building my own scales out of some wood trim slats I had on hand. To make the form of two scales, trace the outline of your blade twice onto your wood stock. After that, clip them out.

Cleaning and polishing your blank is the last step.

Clean your blade. Clean the handle portion of your blank with steel wool and a little light oil (gun oil or 3-in-1 works great). After it’s clean (but not necessarily completely shiny), clean off the blank with some acetone to remove all traces of oil. Mixing oil and epoxy doesn’t work. You can get an idea of what the metal looks like from this image.

Steel wool and a little mild oil are used to clean your blank (gun oil or 3-in-1 works great). Clean off the blank with acetone to eliminate any signs of oil when it’s clean (but not entirely shining). Oil and epoxy do not mix well. This picture gives you an idea of what the metal looks like. Remember, if you don’t have any oils left, your scales won’t stick to the blank. With this stage, you may do as much or as little as you wish. Use a little oil and steel wool to give your knife a more rustic appearance (00, or double-aught, which means double zero). Steel wool is available in three different grades: 00, 000, and 0000. Fine polishing, such as removing rust from a cannon barrel, is done using the quadruple aught. Unless you’re really fastidious, the 00 is good for a knife. In this style of rustic knife, I like to leave a little color.

Step 8: Prepare for the rivets.

Set up for your rivets. Rivets are attractive and will strengthen your knife. Do it right and you wouldn't need epoxy, but I like belts and suspenders.

Rivets are visually appealing and will help to reinforce your knife. You don’t need epoxy if you do it well, but I like belts and suspenders.

You’ll have three rivets through your knife blade in the end. Begin by drilling a hole in the tang, then aligning one of your scales with the handle and drilling through it. Make sure your scale is supported by a scrap piece of plywood so it doesn’t break when you drill through it. As indicated above, insert the rod through the tang and scale plus 1/8′′. That’s where you want to be in the long run.

Place your second scale against the blade and mark it with a pencil, adding roughly 1/8′′. This will come in handy later.

Repeat two more times until you have a scale with holes, a blade with holes, and a scale without holes. If the rod is still stuck in the holes, remove it and use the blade as a template to mark the holes on the scale that doesn’t have any. Make sure you’re drilling into the scale’s backside and that it’s aligned correctly (point end toward the point).

Replace the rod in the first hole on the exterior of the first scale, through the handle, and into the rear of the scale you just drilled. With your 1/4′′ marker remaining 1/4′′ from the scale’s surface, it should be snug. If it’s correct, excellent; hacksaw it off and place the rod in the next hole. Go for it if it will take a little fiddling to get it perfect, and if you will need to drill a little to make everything line up. Just make sure the wood holes are circular. After it is complete, go on to the next hole closest to the blade and continue the procedure. Remove the scales from the blade, but leave the rods in place. A screwdriver or a knife will come in handy.

 

Step 9: Secure your knife’s scales.

Attach your scales to your knife. Mix a little two-part epoxy, about the size of a half-dollar, and spread it on one side of the knife blank. (Do not use five-minute epoxy. It’s weak and doesn’t give you time to work.) Place a scale on the epoxy. Repeat this process on the other side of the blade. Now slide your scales back on the knife blade and tap into place. You might have to use an open vise to allow you to tap the scales into place, but they should go on fairly easily.

Spread a small amount of two-part epoxy, roughly the size of a half-dollar, on one side of the knife blank. (Do not use epoxy with a five-minute cure time.) It’s ineffective and doesn’t allow you to work.) On the epoxy, place a scale. Reverse the procedure on the other side of the blade.

Replace the scales on the knife blade and tap them into place. You may need to tap the scales into position with an open vise, but they should go on quite simply.

After both scales are attached and you’re confident the scales are in the right place, put a clamp or two on the scales and tighten until you see a little epoxy bead form along the edge between the scale and the knife blank. This is called squeeze-out and is a sign that you have a good bond. Once it oozes, stop clamping. You want a little epoxy in the space. Note that there's a LOT more rod sticking out than 1/8". That's because I didn't know how much I would need for a rivet, so there's more like 1/4" or more on each side.

Put a clamp or two on the scales and tighten until you see a small epoxy bead develop along the edge between the scale and the knife blank once both scales are connected and you’re sure they’re in the appropriate position. This is known as squeeze-out, and it indicates that you have a strong link. Stop clamping once it oozes. You’ll need some epoxy in the area.

It’s worth noting that there’s a LOT more rod protruding than 1/8′′. That’s because I didn’t know how much I’d need for a rivet, so each side is around 1/4′′ or more.

I dealt with the excess rod by filing it off. It's soft so it didn't take much.

I removed the extra rod by filing it away. It didn’t take much since it’s soft. Of course, you were wiser than I was and profited from my knowledge. This isn’t something you’ll have to do.

Pein your rivets in step ten.

Vintage Pein your rivets.

The toughest part of doing things on your own is that you can’t always take photographs of each stage. As a result, I’ll try to be as detailed as possible. Place your knife on a hard surface, such as a metal plate or, if you have one or know someone who does, an anvil. Tap your brass rod with the round side of a ball pein hammer (it’s called a pein for a reason), moving the strikes in a tiny circular motion rather than striking it straight in the centre. This causes the metal to swell somewhat. After a few minutes of peining, flip your knife over and repeat. If the rods don’t seem to be equal on both sides, tap the rod on the other side to make it stand out a bit more.

As the rods (now rivets) reach the handle, keep tapping and rotating the knife. Tap a bit harder as the rivet meets the scales to retreat (little) the rivets. Carry on with the other two.

Step 11: Finish the handle by shaping and sanding it. 

Shape the handle. Clamp the handle in a vise and begin shaping your handle. There’s no set way to do this, but I find a 4-in-hand or patternmaker’s rasp works great. Take it easy, running the file mostly up and down at a 45 degree angle to the blade. Work slowly. If you get to close to the blade with your rasp you can dull the rasp.

Start shaping your handle by clamping it in a vise. There’s no one-size-fits-all method, but I’ve found that a 4-in-hand or patternmaker’s rasp works well. Take it slow and gently, generally running the file up and down at a 45-degree angle to the blade. Slowly work on it. If you get your rasp too near to the blade, it will get dull.

Check the handle periodically as you shape with your rasp to ensure it is symmetrical and fits your hand comfortably. Take it slowly; it’s simpler to take off than it is to put back on.

 

When the handle has the desired form, sand it with a coarser grit sandpaper (80 or so), then finer and finer grits until the handle is as smooth as you need. Sand your rivet heads to flatten them a bit as well. Because the metal is soft, the sandpaper will easily cut it.

When sanding wood, you’ll know you’re ready for the next finer grit when no sanding marks from the previous grit can be seen. In other words, if you move from an 80-grit to a 120 or 150-grit, you should not notice any sanding marks from the 80-grit. You’ll have more work to do when you drop down for the next sanding if you shift to a finer grit too rapidly.

Step 12: Put the finishing touches on your handle.

I like oiled finishes, so I used a hempseed oil to finish the handle. You can use whatever suits your fancy.

I like oiled finishes, therefore I finished the handle with hempseed oil. You are free to use anything you want. The more layers of oil you apply, the deeper the appearance will be, plus you’ll be giving your wood a lot of protection.

Step 13: Make sure your blade is sharp.

Wrap cardboard or leather around your finely sanded handle and secure with duct tape. Clamp the knife handle in your vise with the edge to be sharpened facing up. Put on your hearing protection. Using a file, start filing up and down the blade edges, holding the file at an approximately 20–22 degree angle to the blade. Visualize this distance by cutting a 45-degree angle in half. Do not drag the file, as it only cuts on the pushing stroke. Don’t file in one spot too much or you’ll create a low spot, which means a do-over if you want a good, true edge.

Wrap duct tape around your nicely sanded handle and fasten it with cardboard or leather. Place the knife handle in the vise with the sharpening edge facing up. Put on your hearing protection and safety glasses. Start filing up and down the blade edges with a file, holding the file at a 20–22 degree angle to the blade. Cut a 45-degree angle in half to see this distance. It’s not a good idea to move the file since it only cuts on the pushing stroke. If you file too much in one location, you’ll produce a low spot, which will need a redo if you want a nice, genuine edge.

Do a few strokes on one side, then on the other. You’ll see your nice flat edge disappear as you remove metal. Watching this edge is a good indicator of how even your filing is. Most people (myself included) tend to screw up the tip by either not filing it enough, or letting the angle drift toward 25…28…30… Be careful and go slow. Stop when you have a filed edge that looks clean and straight.

Start with a few strokes on one side, then switch to the other. As you remove metal, you’ll see that your beautiful smooth edge vanishes. It’s a good sign of how even your filing is if you keep an eye on this edge. The majority of folks (including myself) mess up the tip by either not filing it sufficiently or allowing the angle to creep near 25…28…30… Take it slowly and carefully. When you have a clean and straight filed edge, come to a halt.

If you make a mistake, start again by filing the blade flat as you did in Step 5. The tip of the blade may vibrate depending on its size. Vibrations may be reduced by clamping a tiny C-clamp to the rear of the blade with a scrap piece of wood (and keep your dogs, cats, and other creatures within earshot from howling at the sound).

Hone the blade in step 14. It doesn’t matter whether you use diamond stones, Arkansas stones, Japanese wet stones, or ceramic sticks to sharpen your knives. You’re just polishing the edge. When you’re finished, test the blade by cutting something (ideally not yourself).

Homemade knife with leather sheath from saw blade.

Of course, you’ll want to construct a knife sheath like this. That’ll have to wait until another day.

Robert Heffern, an AoM reader, was nice enough to provide us the CAD files for this project:

 

  • Knife for sawing
  • Scale
  • Tang

 

 

The “do saw blades make good knives” is a question that many people ask. Saw blades are usually made out of metal, but it is possible to use them to make a knife.

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