This version is designed to simply protect the PCB, but has some issues as it has very thin (0.5mm) walls making it difficult for some 3D printers.
This version allows the PCB to slide in the side, and is held in place by the IDE cable. It has screwholes that match the ones for the metal bracket that holes the original 5.25“ drive in the 246/256 cases.
Under construction: 5.25” drive-shaped mount