Some progress...
first video in motion with new integrated closed loop steppers and Planet-CNC controller board. Quite nice to program the steppers/drives via serial port and the motors will recover lost steps if that should happen. I had to reduce the drive current per motor to 2 amps running or 4 amps while accelerating to not exceed my power supply capability. But still pretty good with speeds up to 7000mm/min (280 ipm) and acceleration of 1000 mm/sec^2 (given the low lead screw pitch of 4mm). I think I will leave it at that for now, way more than fast enough for my purpose. But maybe I get a bigger PS with 60V and 12 amps sometimes....

https://www.dropbox.com/s/h3lpyfltzg..._1224.MOV?dl=0