This is an overhead filament spool holder made for a Lulzbot Taz 5. It will no doubt fit other printers.
We wanted a spool holder that was easy to use and eliminated the filament feed tubes that the original spool holder required. We print with all sorts of weird filaments that break easily, have rough surfaces, and generally cause the extruder to "grind" and stall. This spool holder eliminated 99% of the filament feed issues we were having.
The "on-top" design allows the filament to cascade directly to the extruder head with no friction. The center tube is a 3/4 inch (trade size) PVC tube, available in the hardware store. It has a very slick surface so it allows the filament spool to turn without resistance. The actual outer diameter of the tube is 1 1/16". I included a printable version of the center tube for those that wish to make their own from scratch.
You need two of the spool holders for each filament spool (one for each side, front and back) and you need 6 3/4" of 1 1/16" tube for the center. The spool holder just rests on the top rails of the printer and is held in position by the ridge the protrudes from the bottom that mates with the slot in the center of the printer rail. You change spools by simply slipping the tube out of one of the holders.
We have a dual extruder, so we have two pairs of holders shown in the photo.
If you like, you can secure the tube in one of the holders by threading a screw into the small hole in the top. You can also secure one of the holders (likely the rear one) to the printer rail with two screws and a pair of tee nuts or perhaps regular nuts wedged in the center slot in the printer rail. Seems to work fine for us just resting on the rails without screws, however.
The resolution doesn't really matter
We printed these supports with Innova, because we wanted them to last, but they are super easy to print so they will print will pretty much anything.