I have been trying to think of an easy way to keep the 3D printer fed without using motors and to also not have tangles. This method keeps tension off of the printer head and does not tangle the filament.
Using skateboard bearings was the key since they spin very nice with a heavy spool on them. There's two pieces to this design, the base "table side" and the "spool side" holder. It uses any standard skateboard bearing which is tapped into the spool holder. I printed the spool holder with 50% fill to make it strong so hammering the bearing in does not crack it. The base has four screw holes to mount it to a board.
This works with the 10 pound spools and I can make adapters for other spools if people request.
The "Spool_side_12-25-2014.STL" is for the 1 inch hole spools (10 pounders) and the "Spool_side_2_inch 1-5-2015.STL" is for the standard Makerbot ones. I would be happy to make more sizes if people request. Just ask. :)
Standard bearings: http://www.amazon.com/s/ref=nb_sb_noss_1/189-4144984-6479618?url=search-alias%3Daps&field-keywords=skateboard+bearings
For the spool side, use 50% fill to make it strong. That way the bearing will not split the plastic when tapping it into the plastic. Tap gently to get it flat into the holder. I print the spool holder upside down using supports. Then you can tap the skateboard bearing in using a decent sized hammer. It is tight on purpose so it does not pop out.