4x 3.5" Hard Disk Stackable Stacker

Wanted to play with btrfs raid5/6 and needed a simple way to stack naked hard disks. 2 of these stackers accept 4 hard disks, and can be joined to make an 8x/12x/16x stack, possibly with some feet to prevent the stack from being knocked over while spinning.

The picture shows 4 stacking parts and 4 joiners making an 8x configuration.

Update: added feet parts for extra stability on tall stacks.

Update 2019: Fitting the hard disks was too tight. On prints from my newer 3d printer you almost cant even fit the hard disks in. I made a wider version of the model to correct this. Added a couple more photos.