Theres an ol'boy that lives close to me that makes knives out of old round saw mill blades, some of them are up to 1/4" thick. He will take a dremel with a metal cutting wheel and go around the entire shape of the blade shape he wants, just scoring the saw blade, then take vise grips and start wiggling the metal close to the score, he says they will crack and pop right out. I've never seen him do it, but he tells me this is how he does it, he said this way he doesn't have to heat treat from taking all the temper out of the blade and when grinding just keeps a bucket of water close to keep things cool.
Good Luck
Bill