Ballscrew

Year or two ago I was trying to figure a way to make printable Z-axis for Dollo3D printer and one idea was to use ballscrews. Eventually I went with another design, partly due to the requirement of pellets that can't be printed or are very hard to print. But I did a prototype design with OpenSCAD and recently kinda found it again. Did some cleanup and small fixes and printed a demo piece that works quite nicely. Not sure if I'll ever use the design for anything, but it's a cool gadget all the same.

The ball path is a cylinder-cube hybrid which makes it easier to print since there's no overhangs.

The shaft is designed to be extensible, there's a 'star' shape that can be used to join shafts together.

The design is currently for 6mm airsoft pellets, but the OpenSCAD is parametrized, although not tested very well.

For demo use, print one of each part and extra cap.

OpenSCAD source: https://github.com/spegelius/3DModels/blob/master/Bearings/ballscrew.scad