This harddrive holder for the compact case Inter-Tech IM-1 / Sama IM01 has four 3.5" HDD drive slots and is modular (you could print just the lower two first).

The individual drive holders are screwed together by a couple M3 screws.

It is mounted on top of the bottom fan, to have cooling for the HDDs and a secure mount at the same time.

The holders have rails for rubber HDD screws, to damp vibrations and small holes for additional screw if you want to lock the HDDs in.

With 4 HDDs and a 1200RPM fan the hottest HDDs get to about 45°C under load.

Print settings:

• no supports required for all parts
• recommend printing in PETG or other material with higher temperature resistance than PLA, since it might get soft otherwise, if it gets hot at any time.

Hardware:

• 2x M3x20mm
• 8x M3x10mm
• HDD Rubber Mounting screws with 8mm rubber diameter for the rails (could probably also be printed from TPU)
• 4x Fan mounting screws