Like many people, I have a lot of empty spools and they were taking up a ton of space on my rack. I decide to make a empty spool tower that way I have quick access to them, but they're not taking up very much room. 

This uses a 2" x 48" dowel rod that I purchased from Home Depot, the base is 400 mm but I cut it into four separate sections that way it can be printed on an A1 or an X1c.  I printed several of them they have alignment pins, I've used CA glue to glue them together, but my most recent one I did not glue together. I just let the top section hold it together and it seems to be fine. Your mileage may very.