I have an old Bowie knife I made a long time ago. I use it to cut off pieces of hart pine for kindling. The spine is soft on that knife and after years of beating on the spine with a hammer it has mushroomed out quite a bit. I know this knife will probably not be beat on, but who knows what it will be used for. I have not broken any test blades hardened this way, but plan to soon. Any of you guys broken a blade heattreated this way?