I noticed that the Taz 6 is designed with quite a bit of bearing clearance. See this:youtu.be/18L_bJcZ_i8 (I have intentionally made this not automatically recognized as a link because I don't want this as the picture for this project. It shows the original bearing holder, not the new one).
This results in a visibly uneven surface on printed parts.
The idea here is to cut between the fins of the bearing so that the bearing can be compressed, and squeeze the bearing onto the shaft with the clamping screws.
So far, I've noticed a significant increase in drag on the shaft before the clearance is completely eliminated. It seems most of the remaining play is between the bearing and the bearing holder. I think the solution to this is to fill the gap between the bearing and the holder with glue, and clamp it tightly to the shaft, then when the glue hardens, loosen the screws until the bearing drags only slightly on the shaft.
edit: I tried gluing the bearing into the sleeve. This improved the situation, but when you tighten the bearing enough to remove all play, it increases the friction too much. I also found that there is much more play in the center of the bearings than the ends, so the bearing is only really in contact with the shaft near the ends of the bearing. I think this path to improving the printer is a dead end, so I won't be working on this any more.
Not much infill, but I had it set to 50%
Needs two M3 screws, two washers and two M3 nuts. It is good if the screws drag in the holes as it will keep the screws from getting loose. Otherwise, it might require a bit of glue to keep the screws from turning on their own.