The simplest spool holder

*Update: this thing has been superceded by my newer version located: http://www.thingiverse.com/thing:323930*

I'm a fan of simple and easy to make, so after looking at overly-complicated spool holders, I decided to make my own. I took my dimensions from the SainSmart ABS spool and after making about 20 prints with a spool on this holder I can say that it works perfectly.

This is the simplest, fully functional spool holder on Thingiverse. No unneccesary rounds, no fillets, no cutouts, nothi