3.5to 5.25 case adapter
It is designed to to be 3D printable, recomended material is PETG, put PLA will work just fine.
Features: Allows mounting of 3.5hard drives using the 5.25 CDROM, DVD Blueray standard size mount slot. Fits both 3.5" standard hard drive bottom mounting configurations
Hardware requirements: 4 x 6-32 3/8" machine screws - to mount hard drive 4 x M3 6mm self tapping screws, or #4 3/8 self tapping screws - to mount adapter to ATX case
Dimensions: 156mm long x 146mm wide x 35mm heightFits standard 3.5hard drive mount slot, and holes from the bottomFits standard 5.25 atx CDROM mount slot, and holes from the side
Note: The STL file here is the 6 bottom mount screw, single part version. Not the 4 mount screw or multi-part prototypes.