These are the parts needed to make use of 3/8" rod or tubing that is easy to obtain here in the US. The bearing holder has in integrated IGUS type bushing that when printed in PETG filament has a very slick surface similar to the Drylin material. The parts were tested on 3/8" aluminum rod obtained from Lowes and I also include a bearing holder that is slightly over sized from that in case you get rod/tube that is slightly larger. The oversized bearing holder has ovrsz in the filename.
The XY joiner can be printed at .25 layer height but the bearing holder should be printed at .1 layer height for the best precision. The XY joiner can be printed in ABS but the bearing holder will work best if printed in PET type material due to the lower friction coefficient of that material.