This is a dual 3d printer spool holder made with only off the shelf parts. All but the bearings can be found readily at a Home Depot or other hardware store. The bearings can easily be found on Amazon.

Supplies

You will need: 20 full sized 1/2 inch nuts, 16 1/2 inch jam nuts (half thickness), 16 1/2 inch washers - larger than the bearings, 8 1/2 inch bearings, only the inside diameter is important. 2 1/2 inch threaded rods of a sufficient length, 4 1/2 inch by 5 inch hooks, 4 1/2 inch nuts (8 if the hooks didn't come with them), piece of particle board, appropriate hand tools, drill.

Step 1: Assembly

I do not have good photos of the assembly, but it's very straightforward.

Start by screwing a jam nut onto the threaded bar, on the left hand side, leaving a little room for the hook. Now, from the right, screw on a regular nut. Slide on a washer, then a bearing, and repeat the other way around. Make sure the nuts are tight against each other, but do not tighten them over the washer or the bearing - leave the bearing and the washers free to spin.

Do this again, in the same order, four times on the rod. Adjust the spacing of the bearings on the rod so that a spool will fit on them. As you will see in the first picture, the larger washers hold the spool onto the bearings.

Now, once you are happy with the spacing, do exactly the same process on the second rod.

Now, bolt the hooks onto the rod using the remaining nuts.

Drill holes into the particle board and secure the hooks into the particle board using the 1/4 inch nuts. Make sure the hooks are leveled. Drill two holes for the filament to drop down, and you're done.

Note:

You might want to use small 1/2 inch washers to press against the bearing race. I couldn't find these. It might make it smoother and let you tighten down the nuts better. Also, you might want to put it on a shelf over the printer so it's not affected by the movement of the printer.

You also might want to use a 1/4 inch hose through the holes you drilled for the filament so it is guided how you want.

Step 2: Usage Suggestion

Using an enclosure from makergadgets, drill two quarter inch holes at the top in the same spacing as in the particle board, and feed two plastic hoses up through it. Rest the spool(s) on the bearing, and feed the filament through. Then print away