Just an observation and theory (not original I'm sure): After several recent Normandy hub rebuilds, in all cases, I found much greater damage to freewheel-side cone than anywhere else (otherside cone or hub races)...probably due to unsupported lever-effect.
More to my point (which I'm getting to), I also found, in most cases, the freewheel-side cone to be brinnelled, spalled, or otherwise pitted at a single location along the cone race. I theorize that because the cone does not rotate (like hub races) a single (downward-side) point on the cone takes the maximum load...all of the time! I guess some would argue that a "properly" adjusted and lubricated cup/cone minimizes this effect. I'd buy that...but minimize does not equate to eliminate.
So how to further minimize and/or prevent this damage? How 'bout rotating axle (w/cones) periodically? Easy enough to do but how often? I'll leave that to your discretion.
Except for this disclaimer, the foregoing proposal ignores that present-day riders may be 50 or more lbs heavier than what designers envisioned, along with other contributing factors.
Jack Romans
Sacramento, California