MP Select Mini Reduced Spindle Rounder

This is a redesign of Enzi1984's spindle rounder that is reduced in height and width to allow smaller diameter spools such as the Quarter Turn 5 Dollar Filament Spool Holder by 3DPRINTINGWORLD (http://www.thingiverse.com/thing:2121407). It still works fine with standard 1kg spools.

UPDATE: I've added a modified version of the rounder that adds a raised bumper next to the printer. This corrects a problem with some spools that would migrate too far toward the printer and settle into the space between the rounder and the printer frame, potentially restricting the spool's movement.

Inspired by Enzi1984's MP Select Mini - Spindle Rounder http://www.thingiverse.com/thing:2036976