How to Make a Knife from an Old Saw Blade

Email Print
FacebookTwitterShare

Making a knife is a satisfying project on a number of levels. You’re creating a fundamental tool — one of the first tools ever made — and every time you pick it up, you’ll think, “Wow, I made this with my own hands.” And because you’re making the knife, you’ll be able to adjust its shape to fit your specific needs. The trickiest part of making a knife is the blade. If you have a forge handy, and can get your hands on some good tool steel, that’s great. If you don’t, you can still make a knife using an old Appalachian trick: recycling. That’s what we’ll do in this project.

Old saw blades are almost always made from high quality steel. You can find them in abundance at swap meets, garage sales, rummage sales, etc. The biggest advantage of using an old saw is the lack of metallurgy you need to do. The blade is already the right hardness for holding an edge, so you don’t need to treat the steel to make it a good knife. However, blanks cut from the saw are sometimes a little too flexible, but you can work around (or with) it.

The steel in this handmade knife will not be super-hard. This is not ideal because your knife will lose its edge quickly if you try to hack through wood, slice cardboard, or use it as a screwdriver. But, the good thing about softer steel is that you can bring it back to a razor-sharp edge with a few strokes of a sharpening stone. I actually prefer softer steel as I like a keen edge, and I carry a small sharpening stone with me. If you can shave your arm hair, your knife is sharp enough.

A knife can take many different forms and styles. In this project, we’re going to make what’s called a full-tang knife, meaning that the blade extends its full length into the handgrip of the knife. A partial tang extends only partially into the handle. A full-tang knife is, in my opinion, the easiest way to start making knives. It also produces a solid, sturdy knife that is less likely to break off at the handle.full-tang-knife

Be nice to your knife and it will serve you well.

Materials List

  • Old saw blade
  • Thin cardboard manila file folder
  • Pencil
  • Scissors
  • Chalk or soapstone
  • Cold chisel
  • Hammer to drive the chisel
  • Sturdy piece of metal plate to use under your work
  • Metal files (coarse and fine)
  • Wire brush
  • Coarse (00) steel wool
  • Light oil (3-in-1 or gun oil)
  • Acetone
  • Cloth rags
  • Vise
  • C-clamps
  • Hardwood (oak, maple, cherry, etc.) for handle scales
  • Handsaw (Japanese pull saw preferred) if you’re cutting your own scales
  • Two-part Epoxy (slow-cure)
  • 3/16″ brass rod
  • Power drill
  • 3/16” sharp metal drill bit
  • Ball-pein hammer
  • Duct tape
  • 4-in-hand or a patternmaker’s rasp
  • Sandpaper (80 and 150-grit)
  • Cabinet scraper (optional)
  • Sharpening system of some sort
  • Ear plugs or hearing protection earmuffs

How to Make the Knife

Step 1: Prepare your pattern.

Your knife; your pattern! You can use an existing knife and trace it onto the cardboard, or you can design your own. In this case, I’m designing my own shape based on an old knife used by folks from the fur trade. Use a French curve to make sure your curves are consistent and more importantly, pretty. It’s a universal truth that a pretty shape in a tool or knife is a good shape. When you get to the point that you’re happy with your shape, cut it out with a pair of scissors. In my knife design, I didn’t include a bolster or fingerguard like in the illustration above.

Step 2: Transfer the design to your metal stock.

Using a piece of chalk or soapstone, trace your pattern onto the old saw blade. It doesn’t have to be perfect, as you will be using your eyes as you go, and you will be filing away any imperfections.

Step 3: Score the outline of your blade.

Before you start this step, put on your hearing protection and place a large piece of metal plate under your metal stock. If you have an anvil, don’t work directly on it, as you would be driving hardened steel onto hardened steel. Something’s gotta give, and you really don’t want that something to break off the chisel and imbed itself in your body somewhere.

Line up your chisel with your chalk line, take a deep breath and give it a good whack. It may not cut all the way through the blade, but the score it makes will suffice for now. Overlap the chisel marks as you work around the outline so there is one solid line, not a series of dashes. Take your time.

Step 4: 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.

Step 5: File the blade to shape.

The chisel doesn’t leave the best edge, so you’ll need to dress up the piece with a file. For this step, it’s important to remember that sheet metal is resonant (that’s why people play hand saws with a violin bow). The sound of filing a piece of sheet metal is one of true torture. Minimize this by clamping the blade as close the vise as you can and be sure to wear your hearing protection.

Note: Do not attempt to put an edge on your knife yet. The edge should be perpendicular to the sides of the blade. Look for a consistent stripe the width of the blade. That tells you you’re ready for the next step.

Read the rest of the article

Email Print
FacebookTwitterShare
  • LRC Blog

  • LRC Podcasts