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