Magnetic Gears - Why Nobody Talks About This?

How about instead of a physical-contact gear meshing, a magnetic meshing by permanent magnets? 4-layer & 6-layer PCBs and more: Artillery Sidewinder X2: Discount code(-$49): HEKKA3DX2 Magnetic gears has an engagement that is completely non-contact through magnetic forces, which gives them many advantages, such as much quieter(!) and lubrication-free operation.