Just what the title says, this is a simple spool holder for Ultimachine (and possible other) spools. Should work with any spool with a roughly 40 mm center hole.
Print two copies.
The bearing recess is tight fit, you can warm the plastic to help press fit it in.
With the two bearing in place, sandwich the spool between them and run a 8 mm (or 5/16") thread rod though the bearing. Snug a nut on either side (not too tight). I'd suggest another pair of nuts to lock the first two in place.
You can figure out a mount yourself, either hang it as I have done, mount one end of the thread rod to something, of set the rod across a stand of some kind.
Enjoy your nice, smooth turning, spool mount!