Velleman Vertex (K8400) filament spool holder

This is a filament spool holder for the Velleman Vertex 3D printer (K8400). No support material needed (at least for PLA printed parts).

The STL edition is for a spool holder with the following dimensions:

* Spool hole diameter: 31 mm
* Spool width: 77 mm
* Spool hole "side" width: 4 mm

This corresponds to Innofil3D spools (at least the three spools of theirs I own). The spool holder can be assembled with 4 M3 bolts and nuts or with a cable tie, wire or equivalent wound around the m