I got a bunch of left over maple, cherry and oak pieces from a local cabinet shop. Other peoples trash are my treasure! These are the perfect sizes and species for some awesome knife handles.
Lawn mower blades, metal files and chain saw bars all can contain tough steel of which knife blades can be made. I will admit, however that these can be “mystery steel” as you don’t know exactly what steel you are dealing with. Since this is a low budget hobby for me, I will take my chances. If you can find the quality (Nicholson or others made in USA) metal files, you are probably dealing with some really good steel (from my reading). I’ve had very good luck w/ lawn mower blades once heat treated. I believe most are made with high carbon steel (like 1080 or so). I’m still just learning about the chain saw bar steel.