It occured to me that the problem could be friction. The friction between the X-axis and the TBI ball screws. Now the TBI ball screws are not supposed to be completely tightened because they are supposed to wiggle a little and therefore reduce any z banding that would occur. However the metal bracket (X-axis) is directly connected to the TBI ball screws. And the friction between them is so hight that the ball screws cannot wiggle as designed and therefore cause Z banding. I tried to reduce the friction using lubricants and other methods but the most I could get was loose contact on one end and high friction on the other.
So I designed an Oldham Coupler to be connected between the ball screws and the X-axis bracket. And if I say so myself it has worked amazingly well.
You will need 12 4mm M3 Brass Knurls
6 M3x8 Bolts
6 M3x6 Bolts
Heat the brass knurls and insert in the Plastic parts.
Then screw in the appropriate bolts. The shorter ones go on the top.