Thin Spool for filament leftovers

When there's not much filament left on a roll, but still enough to actually use for printing, keeping it on the 1kg roll takes up space and seems wasteful.

So, use that little bit of filament to print this spool!

Then wait until the next time and wind filament on to this thin spool. It's smaller in diameter than a regular spool, and much thinner. I don't really know how much filament can be wound onto it, but I'd guess it will probably take 50 meters.

Print two of the disks and one of the center ring, then simply super-glue it together.