This thing was originally a small part of a bigger project I made (See http://www.thingiverse.com/thing:290064 )... However, I decided to upload it as its own thing when I realized it can easily be imported and added to any design or thing anyone wants to make that requires fastening of separate parts with a nut and screw... The part is cool in that the nut is permanently confined within any "thing" you add it to - it will never fall out - yet still prints as one piece without ever fusing to the shell surrounding it... It is designed in a way that allows it to spin freely while never separating from the shell or bigger part that encompasses it. With the spinner, I also provided a hollowed out base containing a perfectly sized and scaled screw. Located in the geometrical center of the base, the screw flawlessly slips into the nut with little to no aligning or effort - all while still maintaining a very tight grip...