However, CAD is not the hardest part. The biggest challenge is CAM, i.e., converting 3D design into a tool path.
All free CAM software I saw so far is for a very simple geometry.
I still need to play with Blender CAM maybe…
Anyways, I used FreeCAD Path and it under-milled some parts and over-milled some others.
(no, I am not that stupid, but when you need to mill from both sides it is kind of hard to judge how much tool path generator is misbehaving)
It does not really match the original design, but who cases – it looks cool!