January 31, 2026
Description
The Modular Attached Storage Stack (link) is a compact 3D printed NAS enclosure with expandable bays support up to 8x 3.5" + 3x 2.5" drives.
👉For the premium version of MASS with additional features, please see MASS Premium Page here.
Minimal Part count. Maximum Strength.
Sturdy and simple assembly with 1 screw type for all
Expandable Drive Support
Stackable Modules for up to 8x 3.5” + 3x 2.5” drives
Fully 3D Printable
210x210mm Print volume, optimized for FDM
Powerful Airflow
Quiet vertical airflow with 3x 140mm fans
Customizable
Add a touch screen and other optional features
PCIE Slot Support
5 Drives per Caddy
Capacity for Up to 13 Drives
Handles
Dual 2.5” to 3.5" Drive Adapters
FlexATX PSU support
Addon Fan Modules
Supports development of more MODCASE designs!
| MASS Premium | MASS Free |
Drive Bays | Up to 10x3.5” + 3x2.5" | 4x3.5”+ 3x2.5" |
PCI-E Slot | 1 Slot Low-Profile | NA |
PSU | SFX, SFX-L, FlexATX | SFX, SFX-L |
Fans | 3x 140mm or 120mm | 3x 140mm or 120mm |
CPU Cooler | 66mm tall | 55mm tall |
Printer Requirements | Min. Bed 210x210 | Min. Bed 200x200 |
Core Size (APU) | 210x199x162mm 6.7L | 203x199x151mm 6.1L |
Bay Module | 199x162x150mm 4.8L | 199x150x150mm 4.5L |
Motherboard | ITX | ITX |
Material | 1-2kg PETG | 1-2kg PETG |
Handles | Low profile and standard options | NA |
Display Mod | up to 7" with adjustable CAD | up to 5" with adjustable CAD |
Additional 2.5" Bays | Optional mounts for 2x2.5" drives in a 3.5" bay | NA |
Mechanical PBT | Optional: use keyboard switch as power button. | NA |
Screws: M3x20 (40pcs) - Amazon Option, AliExpress Option
Power Button: Ø16mm - Amazon Option, AliExpress Option
(MASS has been designed to use one screw type for all)
3.5” HDDs (Up to 10 Drives)
140mm Fans (Up to 4 Fans)
5in1 SATA Power and SATA Cables
[Optional] PCIE Sata Expansion Card or PCIE SAS HBA Controller
[Optional] 2.5” HDDs (Up to 13x)
MASS_Instructions.pdf (v1.3)
Note: Optional files are under "other files" section of your printable download page.
Improved fitment for all ITX motherboard types, including boards with integrated IO shield. (Top and Rear pieces updated)
Mechanical Key Cap integrated into Rear punchout
FlexATX PSU mount added to Free version
New Optional Front with no 2.5" drives
New Optional Front with 4x2.5" drives for core module with FlexATX.
(The core can be used as a compact standalone 4x2.5" bay NAS)
Note: Optional Front panels are located in the optional folder. All updates are backwards compatible.
New side panels with integrated displays added
Adjustable CAD templates for side panels
HDMI / USB passthrough added to rear
New 2-Split Bays module added
Tool-less Drive retainer added
Optional screw and locknut option for drive retainer
Bays module has improved clearances for SATA connectors
Note: The old single body Bays module is now in the optional folder. All updates are backwards compatible.
▶How much does it cost to print?
1-2kg of filament. MASS is tested on generic PETG. You can typically find 1kg rolls for $13/kg each (Link), $12/kg if you buy 4 (Link), $10/kg if you buy 10 (Link).
▶Premium vs Free difference?
Premium has PCIE slot support, holds 5 drive per caddy, supports up to 13 drives, has handles, extra 2.5” drive adapters, Flex PSU bracket, addon Fan modules and ongoing updates. It supports development of more awesome designs.
▶Can Free version use premium modules?
No. MASS Free Version was the original model without PCIE slot, making it slimmer by 11mm on the width of the tower, and thus not compatible with the PCIE equipped Premium model.
MASS Free is still a potent enclosure with 4x3.5” bay support and can technically stack up to 8 drive bays using M.2 HBA.
▶Is MASS durable?
MASS is built with an intimate understanding of the non-anisotropic strength properties of FDM. The parts are appropriately designed to overcome layer splitting issues by orientation and print settings. MASS development is committed also to ongoing improvement to ensure it is a durable and reliable option for your NAS setup.
▶How to connect more than 4 drives?
To expand the beyond the 4 sata ports on most ITX motherboards, you can install a Low profile PCIE SATA card on the premium model. You can also use an m.2 SATA controller to add a few more.
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License:
Creative Commons — Attribution — Noncommercial — Share Alike