Huh? What did I miss? Nothing has been solved as far as I can tell.

I guess you can take this to mean two different things...

"Top quality highly polished 700 Professionnel Helicomatic hubs use both an unusual cone and a uniquely fine threaded axle . Neither part is available. 700Pros use a larger chromed locknut in that special thread, also not available."

To me the "larger chromed locknut in that special thread" refers to "a uniquely fine threaded axle ". But I suppose you could take it to mean it's the lock ring on the hub for a larger freewheel. I dunno...