I feel that I need to share this one with you. I have had a lot of problem moving from linear bearings to bushing mainly because of how sensitive bushings are to over constraint. I found it impossible to print two holders that was lined good enough to make the bushings slide as smooth as they do “alone”. One way I found out that works a little is to heat the mounting and let the bussing settle. This however still does not give you that super smooth motion as a “alone” bushing on a rod. And it might mess up lining to other things as well.
I found out that the solution is to remove “constraints” from the bushing mount and only lock the direction that is required, then the rod is the only thing thats lining up the bushings = NO BINDING! And the motion is super smooth! This basic test plate is a easy proof of this (download it and give it a try!)
And if you are running linear bearings give bushings a try. They are silent, cheap and runs fine on drill rod.
stl (12mm rod = 18mm dy bushing)