Shaft Coupling with Spider 3" (Public Domain)

thingiverse

This style of shaft coupling can run you $150 a piece for each individual coupling, not counting the cost of the bronze or rubber spider. Now you can make your own. The spider absorbs any misorientation of the shaft that could cause a bending-moment in the couplings; the spider will fail instead of the coupling and can simply be replaced, but with good alignment the coupling will last for many years. This coupling is used often to transmit significant force as well. This was designed for a 1.5" shaft, but you could edit the shaft diameter to account for many combinations of shafts, with say, a 2" maximum. Ideal material is plain carbon steel for the couplings and bronze for the spider. This design could be machined or 3D printed; it's teeth are designed to be millable with a 1" endmill or smaller. There is a keyway in each coupling, recommend using spring-steel as your key. To hold the shaft on is a 3/8"-16 threaded hole, use with a set-screw. Enjoy! How I Designed This Solidworks!