Originally Posted by
Nuovo Record
Could you post a picture?
If you are talking about 1970s/1980s Record hubs (as used with the Nuovo Record and Super Record gruppos), most (not all!) of them use 3/16 balls on the front hub and 4/16 balls on the rear. Grade is G 25, I think.
Old Record hubs used 7/32" in front, not 3/16".
Nuovo Tipo (usually called just Tipo for short) used 3/16"
Both models used 1/4" in back.
The original Campy bearings might be even finer than grade 25, though I agree grade 25 is good enough.
With most used hubs of unknown provenance, you don't know what balls may have been swapped in over the years, so I wouldn't fret over rescuing the original Campy balls which are likely long gone. Just get grade 25 steel and be happy.
Mark B