spool holder with very little material to print
Simply print 4 of the shims and 4 of the clamps
In addition you'll need:
M8 threaded rod according your spool width
(for 102 mm spools -> 124 mm rod)
4 (old) 608 ball bearings (8mm bore)
8 M8 nuts
12 M8 shims
Please see the pictures for a mounting suggestion.
The 0.5mm step of the printed shim should point to the ball bearing to allow easy movement.
The clamps were designed with support material for easy printing - simply cut it when done!
My work seems to be pretty equal to http://www.thingiverse.com/thing:17473 but you wont' have to fit the bearing into the guides.