NEW VERSION HERE: http://www.thingiverse.com/thing:1070481This spool holder is using 4 standard 608zz roller/skate ball bearings to limit friction. Print two supports then insert the bearings onto the pegs. They are designed to hold firmly the bearings. In theory your spool holder is ready but if you plan on using it without the rollers make sure the supports are stable and that the flanges of your spool are exactly parallel (they often are not !) otherwise you will risk a drop and to brake anything fragile beneath. Space the support so that the flanges will lie onto the bearings. You can put any spool size on it, you are just limited by the size of the frame. To be more secure you can print two rollers to fill the gap between the bearings. You are now limited to spool widths less or equal to the length of the rollers but this setup is more stable. I provided a picture with this setup. Provided STL is for mounting on 25mm Makerbeam (Bukobot).