The local spray welder has a repair facility that specializes in the repair of crankshafts from locomotives. It is an expensive process, but, cheaper than new crankshafts.
I do know for fact he hasnt purchased a riding lawn mower blade in a few decades. If he had a close friend that needed some welding on a gun, he would likely do it. But, that type of work could not sustain his operation, and would be a distraction to it.
Most guns arent worth the effort of an involved repair like that.

Best,
Ted