Spool holder for cardboard spools

These are the printed parts for my cardboard spools that I use for my homemade PET filament from recycled plastic bottles.

The nut needs to be screwed slightly hard to prevent it from turning while printing, the idea is that the nut stays where you leave it screwed on, exerting a pressure on the spool and thus preventing the PET filament from unwinding.

The longer screw is also suitable for conventional spools.