This design does away with all the support that would be required if you made a single spool. Make two prints of the desired size. These two parts form a solid spool after aligning them and carefully bending on all 4 parts of the "stem" to get them to click in place. Update Aug 17th 2020: added 4 more sizes. the name "HalfSpool_25i40f30w.stl" means that this spool has an inner diameter of 25mm, the outer Flange is 40mm (inner + flange + 2.8mm = diameter) and the total Width of the spool is 30mm. I also added the Fusion360 file so you can change the parameters to suit your need. Change "InnerDiameter", "FlangeHeight" and "OverallThickness" to what you want.