There are a lot of filement rack designs here already, but I wanted to make something simplistic. The outcome was an identical design for all corners, with optional accessories such as feet. More coming.   

Print with the flat side with the shallower holes facing down. Use organic support on the build plate only, and a brim is recommended. The deeper hole will be used to mount the horizontal rods, while the shallower hole will face outside for future accessories. You might leave the support inside the shallow holes for now. 

For the rod, I found these 48" long, 3/4" diameter dowels at Home Depot. Built a similar filament rack with this kind of dowel before, and it was still solid after over 3 years. BTW, lumber prices are crazy nowadays. Maybe PVC pipes would be a cheaper alternative? 

https://www.homedepot.ca/product/alexandria-moulding-hardwood-dowel-3-4-in-x-48-in-red/1000115271

The first two layers require 3 pieces of these 48" dowels, and each additional layer requires 2 more pieces. I cut them into 24" and 12" pieces, using the longer ones as horizontal support, while the shorter ones as vertical support. These lengths should be easy to measure and cut in-store. 

I designed with a bit of extra tolerance since these dowel measurements aren't very accurate. Before assembling, I wrapped the ends of the dowels with a couple of layers of masking tape, and the results were perfect. 

Update June 04, 2026: Added labels that just clip on. No glue needed.