I do body repairs on a modern car. It worked fine for mild steel, but as soon as I tried to weld a few welds on the hardened steel sections of the rebar I was dead in the water and there were no more bits to use. Since this type of chisel also has a cutting end, these teeth were destroyed by the chisel shank. It's also a real pain to take the beats off to reverse them. I drilled about 35 spot welds before all the bits were toasted. So my spot welding cost about $1. Not as much. The next purchase of American-made carbide drills.