Easy as pie bushing

For the people who are building linear actuators, especially if you are using a carbon fibre tube as a push rod.
You need to consider that the cf tube is not resistant against abrasion, the epoxy covering the tube will wear out.
If you use a linear ball bushing it will wear tracks in the tube.
Ideally you want a softer material than the epoxy, a sacrificial material which will war rather than the tube.
You don't need full 360 degree support around the tube, 3 points will constrain the tube.
The first pic is the complete assembly and next 2 are exploded diagrams.

The forth pic is the important one .
This is made by drilling a hole the size of your tube in a piece of uhmw or similar material.
You then cut it in to 3 sectors which allows you to cut notches for your sacrificial wear strips.
You can 3d print the whole assembly if you want, just use teflon or uhmw for the wear strips.
You can use more than 3 strips if desired, the pic shows 1 strip per sector or 3 strips in 1 sector. your choice.
What is not shown is 2 screws per sector which allows for adjustments to push the strip towards the tube.

Thats about all, make the housing out of pvc plumbing fittings or 3d print it.
Just adjust the screws for initial setup and then as the strips wears tighten to take up the slaĉk.