I made a 3D printer that uses these bearing! You can find it here:    • The Mulbot - 3D Printed Printer  

This is part of a series of 3D printed linear actuators I am doing. All the actuators use a 28BYJ-48 stepper motor. This version uses a TPU 3D printed GT2 timing belt and PLA pulleys as a drive system. The carriage uses recirculating BB's as bearing.

All the stl's are available for download here:
https://www.thingiverse.com/thing:296...