1/4 Printed BB filled Linear Bearing (BYOBB)

thingiverse

Construct your own linear bearing with self-provided BBs! Featuring four tubes packed with numerous BBs, this DIY bearing comes equipped with a cap secured by two screws. Now available in 1/4", 6mm, and 8mm variants. External attachment is facilitated through zip ties wrapped around the decorative ribs on the bearing. Designed as an alternative to standard linear bearings within the reprap and maker communities, this low-cost option (only $0.35 per unit) includes BBs. Note that steel shot might provide better performance but are less accessible than BBs. For optimal results, print at a layer height of 0.2 mm using either ABS or PLA plastic. If using ABS, glue the bearing together with acetone and melted plastic. Enjoy circulating your BBs more effectively in the "Circulator" version, but don't overpack them; underpack by at least one to account for inconsistent diameters. Out of all my projects, this part stands out as extremely useful!