Effect:  The Magi opens the transparent metal coin Purse and shows a separated nut and bolt, as well as a threaded together nut and bolt.  Removing the separate nut and bolt, and then immediately closing the case, the separate nut and bolt are handed to the spectator of whom it is requested to thread them together.  When he/she has done so, the Coin case is then reopened to reveal that the threaded together Nut and Bolt are now separate.  All can be handed out for examination.  This works on much the same principle as the clear plexiglass Anverdi Nut and Bolt in a solid case, but turns the trick "on it's head" by using a conventional nut and bolt in a see-through case!!  Very clever...