X axis for new CNC machine, based on uni-strut

I've recently discovered how much fun uni-strut is to work with. It is nice and straight, smooth, and has radii on six edges. Perfect for making roller slides!

Since I already have foundry capabalities in my workshop, I thought why not make castings instead of the usual plywood or MDF construction. This machine is going to be quite rigid and precise, I believe.