Here is my third filament spool holder I made for my TEVO Tornado! This spool holder fits securely into the 20x20 aluminum extrusion on top of the 3D printer frame and can be attached without taking apart the frame. It also includes a filament guide arm that keeps the filament from touching the greasy z-rod as it is pulled into the extruder. The design also uses minimal-ish filament utilizing a truss design.

I was hoping that it wouldn't require a long time to print, but nope, it takes a good 13-19 hours to print depending on your print settings. But hey, call it a easy and useful way to test your printer's long printing ability!

Also a little side note, it looks pretty cool too.

While I haven't tested it on other printers, this design can likely be used on all other printers with 20x20 aluminum extrusion like the TEVO Tornado, or printers that have other types of extrusion like 20x40. To test if the filament holder is able to be mounted on your printer, I also uploaded a little test piece that is quick and easy to print and will tell you whether the filament holder is able to be mounted on your printer. I also uploaded a version of the filament holder without the filament guide arm if you don't need it.

To mount the filament holder, angle it backwards so that the larger hook can fit into the top part of the extrusion. Then smoothly position the filament holder vertically while slightly pulling up until there is a noticeable click. This is the secondary hook snapping into place that prevents the holder from falling backwards if it is accidentally nudged that way. You shouldn't need to apply much force if you are slightly lifting up the filament holder as you are rotating it into place.

Make sure to read the printing instructions below.