This is a RepRapable feed spool for Mendel or with slight modification any printer. The design sits on top of the Mendel using y-bar clamps to hold it on. It could easily be made with normal vertexes on the bottom and be stand alone. The frame vertex is a adaptation of Vik's Footed Parametric Frame Vertex http://www.thingiverse.com/thing:2003. You could use standard vertexes and just add washers.
Be sure to check out pictures and more information about my Mendel @ http://reprapbreeding.blogspot.com/
This has now been tested with a 5lb roll of PLA on it and it works very well. I added some more pictures showing this. I also have a video on YouTube http://www.youtube.com/watch?v=BFcND7u_Sqk showing it in action (while printing in PLA that glows under black light)
Cut M8 rod into the following lengths:
3 @ 160mm
4 @ 220mm
Cut 4" ABS to 75mm
Cut 3/4" PVC to 65mm
Print required qty of all printed parts (optional to cut the Spool-side-wood.stl from wood, 22.5mm x 125mm x 6mm thick, and drill a hole)
Assemble as shown in pictures (in detail picture you will notice a stack of washers between spool vertex and bearing, these should not be needed as the file has been updated, but add as required). For the 1/2" PVC pipe I used a hot glue gun to attach it to the inside of one of the spool sides. Optionally print standard or footed vertexes for the bottom and and don't print y-bar clamps. Then assemble as normal.
To use simply remove the center rod for spool, lift out, remove one side, place roll on spool, reassemble and enjoy...