Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3608441.
NOTE!: I've done a print now and i ran into a little problem. The way thing's currently am (i haven't got time to fix it atm) you will have to do a little postprocessing on the axle shaft because it's just a smudge to tight linearly. At the spring end of the axle just cut away the little ledge (1mm ish) twards the spool to leave a little extra length so that the bearings don't pinch. Once that's done assemble an check, you might have to sand down a little on the spring to!
Figured why not have a Multi Material spool holder for the Spannerhands Spool system (even though it's hidden most of the time).
Need to use the spring/clutch assembly, nuts, retaining clips etc. from the original thing: https://www.thingiverse.com/thing:3338467
The axle and axle holder (two holders needed!) from this thing: https://www.thingiverse.com/thing:3490353
And the 1KG version of the Spannerhands Spool System V3: https://www.thingiverse.com/thing:2119644
I borked something so instead of doing "Center and Arrange Models" in S3D you have to do "Align Selected Model Origins" to make the two parts line up. How it works in other slicers i have no idea. Other than that it should be all good.