THIS DESIGN IS OBSOLETE! Please see the newest universal design here: http://www.thingiverse.com/thing:1185076

This is filament spool roller that can accomodate 1kg spools from both MakerBot and DF Robot. The roller uses a couple of patio door ball bearings that you can get from Home Depot for $13. The bearings are notched, which cradles the rim of the spool while allowing it to easily turn. The base of the roller has two slots that allow you to adjust the width of the roller from 65mm to 75mm, so any spool that has a width in that range will work. Check out the video to get some more details, and you can find a list of parts in the instructions.
http://www.youtube.com/watch?v=MXcBH2-0TiE&feature=youtu.be

Parts Needed:
2x Patio Door Roller Bearing (2 Pack)
http://www.homedepot.com/p/Prime-Line-1-1-4-in-Steel-Patio-Door-Rollers-2-Pack-D-1796/100574233#
1x Medium Duty Felt Pads (75 Pack)
http://www.homedepot.com/p/Everbilt-Brown-Medium-Duty-Self-Adhesive-Round-3-8-in-Felt-Pads-75-Pack-49949/203661132#
1x M3 Metric Tap
http://www.mcmaster.com/#8305a32/=qclc3a
1x Tap Wrench
http://www.mcmaster.com/#25605a63/=qclccx
1x M3x8mm (100 Pack)
http://www.mcmaster.com/#91292a112/=qclcjb
1x M3x12mm (100 Pack)
http://www.mcmaster.com/#91292a114/=qclcvm