MakerGear M2 Printer Spool Holder -- 3/4" End Caps

The filament spool mount on the MakerGear M2 works great -- if you have the thick-edge spools like MakerGear uses. For other spools, the mod suggested by http://www.thingiverse.com/thing:37210 works way better (and both can be mounted simultaneously for easy switching). Unfortunately, MatterHackers and some other filament vendors often use spools that have very small core holes, and the rod suggested by Thing 37210 will not fit through....

This is a simple push-on end cap with an interior des