Inspired by cheewee2000's Cable Spool (http://www.thingiverse.com/thing:427024) but wanting smaller file sizes I designed a derivative of the part in OpenSCAD (http://www.openscad.org/) and decided to make it customizeable so you can change it as needed!

Open in customizer or openscad and customize-away! You can export the top, bottom, or both depending on your build volume and spool size.