Using Shims on a Ceiling Fan Blade
If your ceiling fan makes a vibration noise or wobbles, the most probable cause is the ceiling fan blade. The blades of the ceiling fan need to be the same pitch, angle and weight to run smoothly. As the fan turns, the blades cut through the air and cause it to move. As long as all the blades are working in synch to move the air at the same speed and direction, the fan will be balanced and turn smoothly.
How to Check Alignment of your Fan Blades
Before trying to balance the fan, turn it off and wait for it to stop rotating. The easiest way to check the alignment is to hold a ruler to the ceiling near the end of a fan blade. Either note or mark the distance from the ceiling to the tip of the blade. Without moving the ruler, rotate the fan to check the next blade. Continue until all the blades have been measured.
If you find one or more blades out of alignment, loosen the affected blade unit where the blade iron attaches to the fan motor, then slide in a thin shim to correct the angle. You can use an expired credit card or firm cardboard. Retighten the unit and check the alignment again. If too many blades are misaligned or the distance difference is too great, it may be best to purchase new blades or blade irons from the manufacturer.