CubeX printers are available at fire-sale prices via ebay. The mechanism is flawed by a few plastic parts that really should have been made of metal, and indeed, are made of metal in the CubePro printers. When I got my CubeX Duo machine, one of the first things I did was assess its flaws make a plan to address them. First up- replace the plastic Z axis nut plate, then the X axis motor mount (the plastic mount was flexing and tilting the motor because of the tension on the belt).

I cut the Z axis nut plate on a milling machine using a rotary table. The X axis motor mount was fabricated using a band saw and a drill press, so it isn't as pretty, but perfectly functional.

I made the right side Y axis belt clamp plate using the same aluminum. I printed belt clamp bottom pieces using ABS and then replaced the awful acrylic top pieces with phenolic (but may replace those with aluminum just because they are so ugly). The acrylic pieces will break easily if screwed down tightly.

The X axis motor screws were interfering with the left side Y axis belt so I counter-sunk and used flat head screws. This completely eliminates the possibility of belt interference.

I designed and printed a screw adjustable Z=0 switch to replace the silly magnetic, it-only-works-at-one-XY-location sensor that originally came on the machine. It uses a standard microswitch that can be wired NO or NC.