I noted the X axis belts tend to vibrate a lot which has caused variation/texture on surfaces of printed items.
Part of the problem came from the idler bearings on the x axis were not perpendicular due to unbalanced forces of the belt. So the belt was riding the lip on the pulley and causing a vibration. So I made jig to pull the idler perpendicular.
The second part of the problem came from the belt vibrating just due to its natural frequency. So I made a tab that dampens the vibration. But I think it just doubled the frequency, either way, it vibrates a lot less and the surface looks better.
I used an M3 insert on the Bearing Clamp A but you can use a nut, and drill out the hole bigger for any size screw.