I've run into the same with typewriters, I just don't do long distance anymore. One trick I've learned is to wrap a machine in Saran wrap, then block in place with styrofoam and fill voids with spray foam insulation. Quick, easy, but sometimes a pain to un-wrap; but usually no damage to the item. Also a triple wall shipping box like the heavy duty ones from Home Depot can take the weight better. Any chance of brazing the cast pieces? I've occasionally fixed things that way but only works on brass, copper, or iron based metals.