New
#11
Try taking it apart again, then put the blade back on. The vibration seems to indicate you didn't get it back on right. Is the paint job even and smooth?
Yep, doesn't take much to upset the balance of the blades, paint will do it when the coats are not exactly the same. Dust buildup on fans will do it.
It's your choice, could be you just need to re do the paint job. Post a pic of your modded fans if you'd like