I was trying to do some larger prints that required some heavy head movement on the far end of the X axis. The minor slop in the unsupported arm of the Select Mini started to show its weakness and left me with some layer issues. Time to make the X axis support gantry.
Only problem was, all of the good Things were designed for 6mm bearings and I only had spare 8mm rods and bearings. So I remixed it in Blender, added 2 30mm fan slots for future upgrades.
It is still designed to go on top of the existing metal side. If you decide to use the fan ports you will have to cut the appropriate holes in your metal plate. I placed the fan locations so you should be able to mount the fan inside the case if you so choose.
NOTE: I made the rod support hole a smidge large so I could use 1 layer of tape around it. This greatly improves the grip on the rod without having to seriously crank down on the nut and bolt.