I just weighed Schumacher driveaxles some days ago. All weights are per pair, with the wheel axles i.e. complete assemblies. No hex or hex pin though
Original plastic: 14 grams
MIP steel: 18 grams
TiR titanium: 13 grams
My home scales are sh*tty, so the absolute numbers may be a bit off, but the trend is clear. What surprised me was that the TiR shafts were even lighter than the standard plastics (with steel wheelaxles).