Can I used old steel or a saw blade?

One of the first steps of knife making is choosing the steel you’re going to work with. You might have seen some videos or read some articles of people who’ve made knives out of recycled material like old files or saw blades. It certainly can be done, but there are a few reasons that might make you reconsider recycled material and simply buy proper steel. With old and used material, you might get lucky and come across some high-quality steel, but a lot of the time you’re going to find a mystery mix of alloys that may or may not contain impurities. Not only is it more dangerous to shape and heat metals with an unknown composition, it may compromise your end result. If you don’t know what kind of metal you’re working with, you won’t know how to heat treat, quench, and temper it. The metal you plan to recycle may already be heat treated or, as in the case of some saw blades, might have the tips or teeth hardened, but nothing else. Going this route might leave you with a knife that looks okay, but won’t be able to perform—at least in the long run. You can sharpen anything in the world, but the question becomes, “How long can it hold its edge?”