Conical filament spool bearing using BB bullet 50-60

This is a ball bearing for filament spools. The inner diameter is 8 mm, and by making the outer periphery conical, it corresponds to the inner diameter of 50 mm to 60 mm of the spool. Please prepare BB bullet separately for the ball.

The inner frame is divided into two. Inside the outer frame, insert the higher frame inside, Fill the BB bullets and fit the lower inner frame.

Since there is a possibility that the bearing will come off if the core rod put in the center is loose, we added a r