This will walk you through how to make a home-make knife from an old saw blade. The knife I am making is a karambit style, but you can do whatever you want. You could possibly make a knife blank from it as well as a full knife.

Supplies

Needed supplies:

For knife:

One 7 ¼” or more sawblade

An angle grinder

Grinding wheel for grinder

Cutting wheel for grinder

Polisher bit for either the angle grinder or a rotary tool.

A smaller grinding bit for a rotary tool

A knife design (I used a simple Karambit style knife)

A vice or some way to hold the knife down when grinding

Tiered drill bit for holes (not needed for every knife design.)

Wire brush for taking off stray marks (for drillbit)

For handle:

Wood or leather. I used leather, but you can do whatever you want.

Step 1: Designing

Find a design, draw it, cut out the design, then draw it onto the saw blade with permanent marker. (If you mess up, draw over with a dry erase marker, erase it, and try again.)

Step 2: Cutting Off Large Chunks

Put the saw blade in a vise or whatever you are using to hold the knife down, then roughly cut out the shape of the knife with an angle grinder using a cut off wheel. It doesn’t need to be perfect, just make sure you get the large chunks of metal.

Step 3: Fine Tuning

Put the cut-out knife in a vise, then use the angle grinder with a grinding wheel to take of the smaller chunks of excess metal. There are multiple ways to do this, do it the way that works best for you.

Step 4: Finer Tuning

Use the smaller grinding bit on a rotary tool to clean up the edges, and make it look nice. I started out using a lawn mower blade sharpener, but it didn't work so I tried the rotary tool, and that worked much better.

Step 5: Holes

I used this step to drill a hole in the spot needed, you don’t have to do this step if your knife doesn’t have a hole in it.

Step 6: Making It Shiny

Use a drill wire brush bit and rotary tool polisher bit to get off all the dirt or marks on the knife, and to make it look nice and shiny. At this point you may want to temper your blade for strength, by getting it red hot and cooling it fast. I didn't have resources for that, so on to the next step.

Step 7: Rust-proofing

At this point, if your saw blade isn’t stainless steel, you should probably use a clear coat of Rustolium, or another good rust-resistant spray on substance.