still useable?

Are these parts still useable? Countershaft shows some flaking of an otherwise perfect shaft. I know these are available new but cost $60 in Europe.
Is welding and grinding down an option (are the shafts hardened? I assume yes...).

Mainshaft: this is the bearing seat area (rear bearing). Bearing doesn't go on without a press so I assume it is still good.

View attachment 1715856480

View attachment 1715856481
Main shaft is ok. The countershaft needs replaced. Be sure to check the roller area inside the cluster/counter gear also for similar damage.