DIY Brass Nut Bushings for X- and Y-Axes

I am using stainless steel smooth rods (A2/V2A). When I use the standard LM8UU type linear bearings on these rods, the hardened steel balls of the bearings will end up cutting ugly grooves into the rods. Even though I can reduce this problem by rotating the rods by a few degrees around the axis from time to time, I don't like this combination of soft and hard steel.

One solution is to use brass bushings instead of the linear steel bearings. Brass on steel has a very low friction coeffici