remove the grub screws first.
Drill a 10mm hole in a block of aluminium, or through steel not thinner than 5mm. Camfer the edge well.
You will see, that center of the bell will fit in quite snugly, as does the bell of the blue/silver wonder.
Carefully, but with force, drive the shaft out with a hammer. The last part needs to be done with a drift punch.
I took a 3mm slider rod from a CD drive, which I sanded to 2,9mm in the end, so that it does not get stuck in return after the shaft is driven out.
These rods are ecellently suited as shafts themselves, I never use anything different.
Well, after the shaft is removed, you will notice thet the fitting of the bell is to tight to accept a 3mm shaft without considerable force.
Make a reamer from a 3mm CD drive slider shaft: Grind the front side in a way that it resembles a half sphere. Then, at 5mm length, grind away the top half of the shaft.
Use this reamer and a drill press to bring the hole of the bell to the right diameter.
Now you can slide in a longer 3mm shaft without problems, and fix it with the grub screw.