Knurled Bolt 40mm with compartment and Cap

Gift idea - Remix. Added a center hole compartment for a gift card or money. Fun to play with and fidget. Made a Cap from the nut to enclose the end.

Add the nut: http://www.thingiverse.com/thing:1460364, scale to 30.5mm for both X and Y for nice spinning part in between. Without scaling, it is a tight fit.