This is a magnetic coupling concept that uses 10 of the Makerbot 3mm x 3mm x 3mm Neodymium magnets. These comes in handy when you need to couple two shafts together, but don't want to painstakingly axially align the shafts, within thousandths of an inch.I measured the holding torque of the coupling, with the magnets inserted into the couplings in both attraction and repulsion. I used a digital torque meter and analog torque watch, until the coupling slipped and recorded the data below. Attraction: ~43 in-oz Repulsion: ~25 in-oz Accepts a 12mm shaft diameter. I plan to make couplings that have smaller shaft diameters later and I am also working on magnetic gears.Update: Added 3/16" (4.8mm)ID coupling; accepts shaft size of a NEMA 17. Added a 1/4" (6.35mm) ID coupling; accepts a NEMA 23 sized shaft.-Print out couplings and trim ( prints two at a time )-Insert magnets in attraction or repulsion to the other coupling. Magnets will press fit in, but you can use glue or put tape over them to hold them in place.-Put couplings on shaft, and use an M3 set screw or screw to hold them on.-Roughly align the couplings and move them in close to each other.-Now you have two shafts magnetically coupled, without the headache of axially aligning them! :)