I tried using a pulley puller with moderate force to remove the tachometer but it didn’t seem so budge (although I didn’t use heat to soften potential adhesive inside).
Looking at the shaft I can see two slots similar to what I have seen in threaded optical tubes with filters in them. Is there an analogous tool used to thread or unthread tachometers onto shafts? I don’t want to be trying to pull something off that is threaded on. Hopefully this looks familiar to someone and they can advise.
UPDATE: I have tried pulling harder using a pulley puller and a cast aluminum disc that I specially machined for this. The disc buckled and broke leading me to believe the tach rotor is attached pretty tightly and possibly is indeed threaded onto the shaft.