Watertight Magnetic Coupling

thingiverse

This is a prototype of the watertight magnetic coupling for two separate axes. It's achieved by utilizing 12 Neodymium magnets, six on each side, arranged in alternating magnetic polarity. I sourced these magnets from leftover materials in previous projects and they measure about 20 mm or three-quarters inch in diameter. Additionally, you'll need two standard 608 ball bearings. There are two types of pins involved: those that necessitate a hole through the membrane (pins A and B) but are self-aligning, and the universal pins that don't require a hole but demand manual alignment. To ensure a watertight seal, pins that require a hole should also be glued to the membrane. My suggestion is to print them slightly elongated along the Z-axis and then slice them to the correct length where you feel the magnet bearing part is at just the right distance from the membrane. The last image shows the outcome of my attempt to gauge the coupling's strength, which is quite robust. It was the shaft printed with 30% infill that gave way first. The membrane used for testing purposes can be replaced with a nonferrous metal or nonmagnetic material in practical applications. A customized propeller was used for demonstration: https://www.thingiverse.com/thing:116974/#files