UPDATE: 07.07.17 Finally managed to design and lightly test version 3 of this thing: https://www.thingiverse.com/thing:2422558 go ahead and take it for a spin

UPDATE: 18.04.17 If you are using a threaded rod be prepared that the supports will move along the threads and in longer prints can eventually do something bad that will interfere with printing. I'm currently developing a support with a builtin bushing that will spin freely on a threaded rod without moving anywhere. (Meanwhile for threaded rods i recommend using the previous version with 608 ball bearings http://www.thingiverse.com/thing:2067830)

UPDATE: 10.04.17
Added a version for 30mm core, untested

UPDATE
For spool with 57mm hole, print the part scaled to 105% should just work ;)

Second spool of filament has arrived and so i've redesigned the spool support. Same idea is before, very minimalistic design, minimum plastic, minimum parts. This support clips into the spool using 4 printed springs, no other fasteners required, no screws no nuts.

Low profile so you might be able to fit 3 spools above your printer, although that's probably not too healthy for the acrylic frame ;)

Printed in PLA, and apparently there is enough flex in the springs.

Spool ID - 54mm

Consider printing slightly hotter then usual for better layer lamination.