Response from Steve. Hope it helps you, Jim.
Unless the tines are completely mangled I'm sure they could be reworked. My tiller doesn't have any "cutting edge" on the tines so there isn't anything to sharpen that I can see. If the edges are all peened over or rounded from hitting rocks and they just won't penetrate the soil, I would probably take 'em off and grind them with an electric hand grinder to restore the shape of the edges and that's about it.
Unless the tines are completely mangled I'm sure they could be reworked. My tiller doesn't have any "cutting edge" on the tines so there isn't anything to sharpen that I can see. If the edges are all peened over or rounded from hitting rocks and they just won't penetrate the soil, I would probably take 'em off and grind them with an electric hand grinder to restore the shape of the edges and that's about it.