The problem with circular saw blades are,you never know what type of steel they are.With an unknown steel you don't know the proper heat treatment/ temper process.It's just a trial & error until you can find something that will make a blade that will hold an edge without being brittle or too soft. Some blades with carbide teeth are non-hardening steel,after all why waste money on good steel when the carbide will do all the cutting. When just starting to learn knife making,stick to a known type of steel.But,that's just my opinion.