This fun little puzzle was an interesting task, and a great excuse to do some threading on the 1954 Monarch lathe at NDSU. The goal of the puzzle is to get the two threaded rings off the two-headed bolt. At first the task seems impossible, as the rings can thread off the piece into the grooves on the end of the piece, but there seems to be no way to remove them. The trick to the puzzle is that the bolt is made up of two pieces that are held together by a left-hand thread, but the seam between the two parts is invisible to the naked eye. When I give this puzzle to friends, coworkers, or fellow students, the hint I always give is “The more you know, the harder it is!”. The more mechanically inclined people are, the harder it seems to be for them to solve the puzzle, as lefty-loosey righty-tighty has been drilled into their brains. Over the years several people have threatened to run it through a bandsaw out of frustration, and it has provided a lot of good laughs.
