The Method The Mechanic Chose to Repair a Broken Solid Pinion Shaft is a Very Commendable Process.

[@GaisaSanktejo]

I believe the repaired shaft would have been stronger if you used the lathe to cut out the visible defects, then re-welded it, then repeated until ALL defects were gone.
After that, the repaired shaft would require proper heat treatment to maximise its life.

[@احمدبنيوسف]

يجب غرز اللحام....وخراطة الجزء الملحوم فقط