The art of making knives is an ancient craft requiring skill, patience, and experience. This article describes making a knife blade out of an old circular saw, which means you won't have to heat and temper the steel. If you're just getting started with making knives, or you want to make a blade just for fun, these steps will explain how.
Put the knife on the circular saw and trace the outline of the blade.
Clamp the saw blade tightly to the table using the vise or c-clamp.
With the drill or drill press, make holes along the outline you traced. Make the holes as close together as you can without having them overlap. Create a perforation around the outline, rather than cutting the shape from the saw.
Replace the drill bits as they dull. You will need several drill bits depending on the size of the blade because the hard steel of the saw will wear them out.
Readjust the clamp so that it's holding the blade you outlined.
Hit the area around the blade with a hammer to knock it off. Hit one side, then flip it over and hit the other until it breaks off.
With a file or belt sander, smooth the perforation from the edges of the blade. If you're using a belt sander, work slowly to ensure the metal in the blade doesn't heat up too much. The steel should never be too hot to touch, or it will weaken and break easily.
Use the file to mark a notch in the blade near where the handle will be.
Clamp the handle part of the knife to the scrap of wood, then clamp the wood to the table.
Bevel the cutting edge with the file. Shape the blade a little bit at a time. For each stroke of the file, flip the blade over and do the same stroke on the other side so that you're removing equal amounts of metal from both sides. Do this until the blade attains the shape you want.
Use the belt sander to grind a straight, thin cutting edge along the blade. Do this slowly and carefully to avoid heating the metal too much.
Polish the knife with sandpaper. Start with a coarse grit sandpaper to remove the cutting lines from the blade and cutting edge, then change to increasingly finer grit to achieve the polish you want.
Always wear protective goggles when working with metal. Slivers of flying steel can easily blind you.