When I printed the “ATX PC bench case” from Chyneuze, I found out it wasn't actually ATX but mATX and my motherboard didn't fit the thing because the screw holes didn't line up.

I then took his work and modified it, so it can fit an ATX motherboard. I also changed the tolerances a little bit as for me the printed parts had an inner diameter of around 14,5mm - 14,7mm instead of 15mm.

Furthermore I changed the radiator mount to comply with the wider motherboard and still be able to fit a 240mm radiator as well as a 360mm radiator. 

For those using an air cooler and wanting full stability I added modified parts for an aluminium pipe. Just use a 340mm long 15x15mm aluminium profile to connect the Top_stabilizer_Left and Top_stabilizer_Right parts. 

Theres also two simple caps for those, who don't want any extra stability, which I wouldn't recommend though. 

Tl;dr:

print following files for 240mm radiator system:

• 01
• 02
• 03
• 04
• 05
• 06A

additional stuff needed:

• 2x 450mm 15x15mm aluminium extrusion

print following files for 360mm radiator system:

• 01
• 02
• 03
• 04
• 05
• 06B

additional stuff needed:

• 2x 450mm 15x15mm aluminium extrusion

print following files for air cooler max stability system:

• 01
• 02
• 03
• 04
• 05
• 08B

additional stuff needed:

• 2x 450mm 15x15mm aluminium extrusion
• 1x 340mm 15x15mm aluminium extrusion

print following files for minimum stability:

• 01
• 02
• 03
• 04
• 05
• 09C

additional stuff needed:

• 2x 450mm 15x15mm aluminium extrusion

Have fun!