The most up-to-date assembly manual for the Octominer frame is at: http://spotswoodcomputercases.com/?page_id=9212
Attach a post to a short beam using a M3x20mm bolt and washer (the bolt is inserted through the short beam).
Insert two hex nuts into the bottom groove of the short beam.
Using the two hex nuts, attach two rubber bumpers to the post-and-beam sub-assembly via M3x6mm bolts.
Attach the second post to the sub-assembly.
Assembly another post & beam sub-assembly, but without the feet.
Assemble a third post & beam sub-assembly, with feet, but without the second post.
Using M3x35mm bolts, washers, and nuts attach a long motherboard support beam to the three sub-assemblies (the long bolt goes all of the way through the corresponding holes in the motherboard beam and sub-assembly beams).
Repeat to attach the second (middle) motherboard support beam.
Attach the PSU support using M3x20mm bolts washer and hex nuts.
Insert 8 M4 hex nuts into the milled GPU support beam. To prevent the nuts from sliding out of the groove, “capture” them via two M4 Phillips head bolts.
Attach the GPU support beam using M3x14mm bolts washer and hex nuts.
Loosely attach the 17 hex standoffs to the frame using M3x20mm bolts. (TIghten the bolts after the motherboard is secured.)
Using M3x8mm bolts, washers, and hex nuts attach 6 black plastic PSU mounting “tabs” to the back of the frame.
Insert 6 hex nuts into the grooves in the two fan support beams.
Attach the two fan beam to the frame via M3x20mm bolts, washers and hex nuts.
Using M3x8mm bolts, washers, and hex nuts attach 6 black plastic PSU mounting “tabs” to the back fan support beam.
The PSUs are attached to the black plastic fan tabs with three #6-32 bolts and washers.
Fans near the front of the GPU brackets are attached to the frame via the 6 black fan tabs (the same tabs to mount the PSUs), along with M3x35mm bolts.
Fans at the tail-ends of the GPUs are attached directly to the frame via M3x30mm bolts and M3 nuts that are inserted into a slot in the extrusion.