I've had good luck with making the mechanical parts of the jig from PCBs. It's just so cheap to get small quantities of boards made now, and you're laying out

I've had good luck with making the mechanical parts of the jig from PCBs. It's just so cheap to get small quantities of boards made now, and you're laying out the main PCB anyways... A neat OSS toolchain for this, is KiCAD for the PCB, and FreeCAD for any 3D mechanical bits required. There's rapidly-improving integration between the two, so for instance the PCB can be brought in to the 3D space.