a few linear ball bearings
thingiverse
I drew a few more linear bearings. Two are identical to the previous one, with straight channels closed in a single ring. And two others - ta-daammm! - with spiral channels! O_ O. https://youtu.be/ner6ghTDctM. Both can work on 10mm and 8mm shafts. The spiral bearings revealed an interesting feature - they can function as ball screws. Based on such a bearing, you can make a simple actuator with anti-lock protection!
Download Model from thingiverse
With this file you will be able to print a few linear ball bearings 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 a few linear ball bearings.