We use large truck leaf springs all the time for building up loader teeth and excavator teeth in gravel pits. I built a 5 foot grader blade a few years ago to clean up a section of woods buy grubbing out sapplings and cut down some hard ground. I made thhe blade out of a half lf a 24 inch pipe wich gave me an agressive cutting action. But it wasnt grubbing right and I couldnt cut the clay. I cut off several leaf springs into 4 inch teeth and welded them to the cutting edge. I cut down several hills with it and the teeth showed very little wear over the year. I sold it to a customer of mine that has been clearing the woods around his house the last couple years with it and he finall wore 2 of te teeth off with the cutting edge.