Here's a picture of the weld on the knuckle of my Dana 25 axle, which (AFAIK) dates from c1949.� I had sandblasted the axle housing, but the morning dew got to it leaving the rust pattern you see (which was easily cleaned off).�

It's the circumferential weld that really intrigues me.� The other welds (the one holding the brake hose holder in the picture, and the ones on the spring mounts, not in the picture) are clearly done by hand.� But this one weld is not--it's a much higher quality.� Since they didn't have robotic welders in 1949, how did they do this?
This is just curiosity--I have no inclination to try to do anything like this myself!
-Paul