I have slightly modified the great design of the Bearing spool holder from chylld www.thingiverse.com/thing:7001.
I fits reels from www.watterott.com and www.reprapsource.com which seems to come from orbi-tech.de.
The bearing holders are designed to fit a 608 bearing and they are placed into the spool centre holes, with lips to stop them from going all the way through.
Print 2 of each part (2 bearing holders, 2 spool sides, 2 'a' feet, 2 'b' feet). a and b feet are from the original thing www.thingiverse.com/thing:7001
Assemble with 8mm wooden dowels of the following lengths:
1x 14cm - between the bearings
2x 27cm - base (long)
2x 16cm - base (short)
4x 23cm - diagonals