I understand'ya, Terry- My wife worries about me disturbing the neighbors with my 3:30AM bright flashes of light, clang-banging, and hideous, evil laughter... and always worries about what strange monster she might find in the shop or driveway when she wakes up...
But to properly fix that shaft, you'll be pulling the engine apart. If you've got a lathe, and you're good with oven-baking and welding up cast-iron crankshafts, you could do it yourself, then grind it back to spec, and re-cut the keyway...
...but it'd be a whole lot more sensible (dollars-and-cents-aible) to stick a different crank in it. While you're at it, give it the obligatory bore, rings, piston, and governor gear, deck the block, true the head, install gasket & seal kit, and rock-and-roll!