Mac Mini 4x SSD + USB Hub Expansion Unit

This expansion hub sits below your Mac Mini / Studio and has room for adding up to four 2.5" SSDs and a USB hub.

I recently decided to use a Mac Mini as a home server, but I needed to find a way to add more storage. I previously upgraded the two internal drives to SSDs, but I still needed storage. I considered a variety of products, including the popular Satechi-style hubs, which have room for one SSD or an M.2 drive, but I wanted more storage. The OWC Mini Stack also looked promising, but they also have only two drives. So, I decided to make my own.

This expansion hub is the same footprint as a Mac Mini and fits perfectly under or on top of it. It has rails on the base that accept up to four 2.5" SSD drives (or HDs if you want to go that way). They slide into the rails from the side and are secured with a single M3 screw (opposite the connector end).

To connect them to the USB hub or directly to the Mac Mini, I used a Sabrent SATA to USB 3.0 adapter (Amazon.com link). Other options are available, including USB-C versions if you have a newer Mac Mini. But I have a 2012 Mac Mini with USB 3.0, and these were inexpensive (less than $10 as of today) and relatively small compared to some of the others. The cables route under or between the drives and are held in place by a set of cable channels at the back.

On top of the cable channels is a hold-down block that screws down on top with two M3 socket-head screws. This keeps them nice and tidy coming out of the back of the expansion unit.

Thes drive cables can plug directly into your Mac Mini's USB ports, however I wanted to leave a few of the USB ports open for other accessories like a keyboard and mouse. So, I opted to integrate a USB hub into the expansion unit.

For the Hub, I went with a powered, 4 port USB 3.0 hub from Amazon (Amazon.com link) for about $20. If you use a hub, it is important to get a powered hub as four SSDs is too much for a single USB port.

The hub sits perfectly in the sunken area at the back on the back and can be affixed with double sided tape or hot glue (my preference). The USB hub and power cables have cable channels next to the ones for the SSD cables. See photos for reference.

If you opt for another USB hub or don't want one at all, you will need to modify the sunken area and top to close off the area.

Then, all the SSDs can plug directly into the USB hub, giving you four SSDs connected through a single USB port. I'm mostly using it for general file storage and a Jellyfin server, so high performance is not my main criteria. If it is, you should plug them directly into the Mac Mini.

The top case fits perfectly over the base, like a clam shell. It's relatively thin, but is designed so the perimeter has a lip that sits on the base and the SSD rails touch the top, making for a perfect fit. This way, the weight of the Mac Mini (if stacked on top), is carried by the base.

I used some strips of foam rubber for the feet on the bottom. Since the SSD rails carry most of the weight, be sure to add feet directly below them. See the photos for reference.

Ventilation is provided by the cutouts on the bottom of the base and vent out the holes on the back of the top.