Filament spool holder to adapt from the ~32mm OD rod on the Creality machines (I'm sure other machines use that size too? I'm relatively new to this whole 3D printing thing) to the 50+mm ID size common on many filament rolls. Contact area with the spool is limited to <1in^2 to minimize friction and optimize spool payout of the filament during printing. I've been using it for months, it works great!
.stl file available