Linear Bearing For Square Tube

This is the DIY linear bearing I came up with for my carbon arc furnace project. This bearing will eventually be the Z axis that keeps a carbon electrode a constant distance above the molten metal in a crucible. It is based on skateboard or roller skate ball bearings, aluminum square tube, and common hardware. Similar designs have probably been used by many others. Many thanks to my friend Chris for letting me use his band saw and mini mill / drill press, which made quick and precise work of these parts.

Here is my Electric Arc Furnace playlist:

https://www.youtube.com/playlist?list=PLlYTxvu80_kElXv1LZdk-mw1ap3W5PuQT

Here is my Electric Arc Furnace page:

https://hildstrom.com/projects/electric_arc_furnace/index.html