Tim Schwartz wrote:

I've got a Tandberg 3001 here where the small plastic gear that drives
the tuning pot (opposite end of the shaft from the tuning drum that the
dial cord wraps around) has cracked.

Plastic gears can be repaired by melting new nylon or derlin into them
with a soldering iron, even missing teeth, and cracks around the hub
can be prevented from reappearing by pressing a ring of metal around
them.