This is a fully parametric threadless ballscrew design used for linear motion with no backlash! It is based on the original design of MSollack, and a re-write of the thing from RifRaf (http://www.thingiverse.com/thing:124800) . This is a model with dual bearings for higher precision and torque capabilities! The "stock" v2-1 openSCAD file is designed for common/cheap 608zz bearings. I did a lot of code re-work so hopefully it'll take set of parameters much better than the initial version! Video here: http://www.youtube.com/watch?v=Rkhm-hp9788 This should be fully customizable, enjoy!I rotated mine in the slicer (KISSlicer) to that is was standing on the base instead of lying flat. Also used "rough" supports 0.2mm layer heights, 25% infill (minimum, higher for durability) With default customizer settings: 3x M8 bolts (for bearing axle) 3x M8 nuts (for bearing axle) 3x M5 bolts (secure base, bearing compression) 3x M5 nuts (secure base, bearing compression) 1x 10mm rod 6x 608zz bearings (22mm OD x 8mm ID x 7mm H) I haven't fully finished tweaking the code yet, but it should work as is. However, you may have to adjust GapTolerance depending on your printer... I've printed the "Threadless Ballscrew-v2-15x3bearing.stl" using 696ZZ bearings (6 ID x 15 OD x 5 H) and M5 bolts and the "threading" action works GREAT on it. It is a very tight fit on my printer though, so I've adjusted the default GapTolerance to 0.95 instead of 0.96. It was actually so tight at 0.96 that it cause the frame to slightly separate instead of using the compression nut to generate extra tightness. I believe the force required to just push (by hand) the rod to make it slip through the bearings is > 50 lbs with my current setup, I'll post a picture tonight of how it looks Things left to do: Verify Angle of bearings match pitch specified in parameters. Test an idea I have or further increasing the torque handling