Integrated Slide Rails
thingiverse
If you need for two parts to slide against each other in a neat, predictable way, then guide rails is the way to go. These are not meant to be printed out on their own, but integrated into and included on your projects. See below for instructions.
Download Model from thingiverse
With this file you will be able to print Integrated Slide Rails with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Integrated Slide Rails.