This is a CoreXY 3D printer design that has some features that should be appealing to many:
1) it uses tubular extrusion (square 20x20mm) Aluminum or Stell so it should be cheaper than T-slot;
2) all the cutting and drilling can be done by hand as the design is very forgiving with straight cuts being unnecessary; just a few holes need to be precisely drilled with a 90 degree jig or a drill press.
This version has fixed Y clamps, unlike the 4-point-adjustable clamps I show in another model so the frame must be dead square.
This will be eventually built and uploaded to thingiverse/instructables.
Enjoy.