The tensioning is not ideal, but works fine. I have some changes in mind, but I want some of the parts to be plasma cut, so I am holding off rev 2 until the machine can do it.
The tensioning of the belts took about three hands to do so I added 2 tapped holes through the sides of the UHMWPE (not shown in rendering). Bolts through the holes push the motor to tension the belt....it works great. You can't see it from the rendering, but the motor is in a pocket so the shaft can stick out enough.
I use a USB smoothstepper on my big router. It works best when you have a really high step rate (I have 28800 step/in) . I like it, but I have had some problems with it. If the computer cannot respond fast enough via USB, the smoothstepper locks up and gives a error about the USB speed. Mach3 has no idea where it stopped. You have to restart Mach3 to fix it. I bet the Ethernet version has the same issue. Get a fast computer and try not to watch YouTube while running a job
Bottom Line: I like it for the router.
Obviously the parallel port is a dead end, but if you use special applications like close loop torch height control, that has to be programmed into the hardware of a device like a smoothstepper or it will not work.
I wanted to use an off the shelf solution to start with because I have never used a plasma. After that I have a group that wants to help do an open source replacement for everything.