said by leibold: said by dont rig it :
And definately check the blade.
Are there any good/quick/easy DIY solutions for balancing a vibrating fan blade ?
First check I'd do is to set the blades down on a flat surface and make sure that all the blades touch the surface. Flip the whole thing around and check the other side too. This will ensure that none of the blades are bent out of alignment. If any of them are, you can bend them back to try to get them in-line with the other blades as much as possible.
You can also check that they are all about the same angle.
Another check you can do, is to balance the blades with a pen through the hub where the motor shaft would go. If any side of the blade set is heavier (out of balance), gravity will cause the blades to rotate so the heavier side is at the bottom.
If the blade set is well balanced, you can turn it to any position and it will stay put.
If the blades are heavier on one end, and you've checked that the alignment and angle of all the blades is the same, then you can attempt to balance it by grinding away a small amount of metal from the edge of the heavier blade (the one that settles at the bottom).
It's not the perfect method, but it generally works well enough.