Modular ITX/DTX/mATX/ATX/SSI-EEB/SSI-CEB/EATX/XL-ATX mainboard frame/tray

Introduction This is a simple PC mainboard frame/tray system intended for open-air or custom enclosure PC builds. The intent is to support a broad variety of mainboards from iTX to so-called EATX with modules that fasten together with M4 nuts and bolts. Version log v3.1 (2026-01-17) M4 fastener holes increased from 4mm to 4.25mm diameter to ease fitment add "I/O shield" text to indicate orientation of mainboard added back single piece matx for larger printers like Core 1, P1S, U1, etc. added 1.85mm "trimmed" versions of "EATX" parts to correct standoff locations for some boards added fastening holes for upcoming I/O shield and PCIe card holder parts v3 matx1 piece adds a protrusion for an optional standoff location itx and atx parts add optional standoff locations for SSI mainboards re-uploaded files with “medium” detail level to reduce file size v2 added missing standoff hole on atx2 all standoff and frame holes same size add 0.25mm filets to all edges v1.3 matx updated to be 4 pieces instead of 1 to print on smaller printers v1.2 added SSI mounting holes recessed landing pads for frame mounting screws added legible part name inscriptions v1.1 initial design concept Required parts mini-ITX/mini-DTX/ITX 1 part (itx.stl) 4 mainboard standoffs optional: 4 screws to secure frame to other components DTX 2 parts (itx.stl & dtx.stl) 2 nuts/bolts + 4 washers to fasten parts together 4-6 mainboard standoffs optional: 4-6 screws to secure frame to other components micro-ATX (mATX) 4 parts (itx.stl, dtx.stl, matx1.stl, matx2.stl) 4 nuts/bolts + 8 washers to fasten parts together 5-8 mainboard standoffs optional: 4-6 screws to secure frame to other components micro-ATX (mATX) alternate for larger printers 1 part (matx-full.stl) 5-8 mainboard standoffs optional: 4-6 screws to secure frame to other components ATX 4 parts (itx.stl, dtx.stl, atx1.stl, atx2.stl) 5 nuts/bolts + 10 washers to fasten parts together 6-10 mainboard standoffs optional: 6-8 screws to secure frame to other components EATX (SSI-CEB/SSI-EEB/XL-ATX) 6 parts (itx.stl, dtx.stl, atx1.stl, atx2.stl, eatx1.stl, eatx2.stl) 7 nuts/bolts + 14 washers to fasten parts together 8-15 mainboard standoffs optional: 8-12 screws to secure frame to other components Fasteners M4 nuts, bolts, and washers to secure frame pieces together M3x6x6 mainboard standoffs and m3 screws to secure mainboard to frame When fastening the frame to a table or other components use washers to spread the load! Exterior measurements of the parts itx: 170.330mm x 171.600mm dtx: 170.330 x 72.240 matx1: 171.6 x 45.720 matx2: 72.240 x 45.720 matx-full: 216.050 x 243.840 (243.840 x 243.840 extended version) atx1: 134.470 x 171.600 atx2: 134.470 x 45.720 eatx1: 134.470 x 86.360 (134.470 x 84.5 trimmed version) eatx2: 170.330 x 86.360 (170.330 x 84.5 trimmed version) Notes Accepts 6-32 and M3 motherboard standoffs. Holes are 3.25mm in diameter gradually tapering to ~2.3mm to grip the standoffs. This may be adjusted in future revisions. Extra holes are added to accommodate SSI-style boards in addition to ATX style boards 10mm z-height - combined with ~6mm high mainboard standoffs provides ample clearance for PCIe card tabs Can use a variety of fasteners to attach the frame parts together and/or secure the frame to a surface or custom chassis. Fasteners can be up to ~4mm in diameter. Washers should be used to spread the load against the plastic to avoid cracking PETG recommended for durability/flexibility, but PLA is OK. For environments where air temperature exceeds 60°C, ABS/ASA is probably a better long-term material. Most 3D-printed materials are non-conductive and can build-up static charge. I doubt its necessary, but to mitigate static, ~28awg wires terminated with spade connectors can be run between a few motherboard standoffs and then grounded to the power supply. References for mainboard sizes and standoff locations https://web.archive.org/web/20160817033942/http://www.formfactors.org/developer/specs/atx2_1.pdf https://www.snia.org/sites/default/files/SSIF/2018-05-31/SSI%20EEB%202011%201.0.1.pdf https://digitallibrary.intel.com/content/dam/ccl/public/600565-btx-specification-update-rev1p1.pdf https://linustechtips.com/main/topic/812415-ee-atx-standoff-locations/ https://www.gamersnexus.net/guides/3566-e-atx-is-a-lie-vs-xl-atx-eeb-ceb https://en.wikipedia.org/wiki/ATX#Variants https://hardwarecanucks.com/forum/threads/lets-go-team.12383/page-432#post-527475 https://www.silverstonetek.com/it/tech-talk/wh11_008 To-do Design add-on parts to hold a clip-on I/O shield and PCIe cards