Without getting into whether or not China does or doesn't have this level of manufacturing capability, I would suggest that it's not a case that the socket requ

Without getting into whether or not China does or doesn't have this level of manufacturing capability, I would suggest that it's not a case that the socket requires less precision; it's that making a socket to the tolerance required is significantly easier than making the sphere of metal to the tolerance required. They both have to be precise; the ball is harder to make to that precision.