How to correctly identify bearing cones for axles, to find replacements?
I find it rather difficult to get cones by themselves in Germany. It is much easier to get an entire replacement axle with cones. Often enough I found the whole assembly to cost less than an individual identical cone.
The good thing about cup-and-cone hub bearings is that there are only two ball sizes. The front always has 4,762 mm (3/16 inch) balls. That means also the races on the cones will fit.
When the outer diametre fits as well and the cones have about the same length a different axle with their cones might do.