About this 3D model

If you are using a threaded rod (3/8 inch) as a spool holder these keeper nuts will thread onto the rod and hold the spool bobbins (such as [thing 316826](http://www.thingiverse.com/thing:316826)) in place. rev_A - too tight, hole closed slightly when printed. rev_B - fixes the hole size to account for shrink rev_C - removes the sharp points that hurt my fingers