I designed this filament shelf to resemble a well-known technical brick but at a much larger scale. Each lift arm can support up to 20 lbs, meaning a pair can easily hold up to 11 rolls of filament. 
 

For the axle, you’ll need a ½-inch steel conduit pipe from your local hardware store, cut to the length you need (I cut mine to 32 ¼ inches or just under 82cm). The axle pieces slide onto the conduit to form a giant, axle and snap together without glue. I’ve created two versions of these axle pieces: one at 200mm and another at 100mm. The 100mm version is much easier to print, so I recommend using that one—especially if you’re worried about your bed adhesion.

The cleat mount is designed for both strength and a clean appearance, as it hides the mounting screws. To ensure maximum durability, print the cleat mount with 100% infill and at least 3 to 4 wall loops.

The width of the shelf is determined by the wall studs, which are typically 16 inches apart. For my setup, I skipped a stud, making the shelf just over 32 inches wide.

You can customize the length as needed, but be sure to mount the lift arm pieces securely into wall studs for proper support.