Teac A-3300 A-3300SX A-3440 A-3440 fly wheel and other Teac machines
This is a nice flywheel from an old TEAC A 3440 and probably will be common in other reel to reel models from TEAC, it has a 6MM shaft hole
its slightly bigger than newer models.
I have seen its the same in A3300 A3300SX
It appears they are balanced and you will see several holes drilled around the inner rim to get them just correct