I designed this a very long time ago, but I never posted the files. Every so often someone asks me for them. It is a fan mount that can attach either to your X carriage or to a RepRap Mendel's X carriage. Thanks to StefanHH for his original ball socket design!

This is a tubular drive mechanism. It is designed to use 1/2 inch aluminum conduit. This is a work in process, and I am already working on a newer version that will use dual rails. I think that this type of mechanism will work well as an linear axis drive mechanism when combined a stepper motor, and magnetic linear encoder would provide high accuracy large scale positioning.

Tubular Drive Test Fixed Drive
youtube.com/watch?v=k0G8B77UOJs

Tubular Drive Test Fixed Conduit
youtube.com/watch?v=70dTRN7zSpU