I acquired an older model Shopsmith Mark V for next to nothing from a lady while on a service call. Several pieces were missing, one such piece being the coupler that connects the motor to the bandsaw. Shopsmith sells this adapter for $32, but I'd rather make something than buy it if I'm able. As you can see, my first coupler was made out of PVC pipe and epoxy. I've been using that coupler for over two years now with no trouble. Now that I have a 3d printer, though... why not print a new one?
Before you print the full coupler, you may want to print the test piece and make sure that the sizing is correct for your connector. The coupler may need to be sized up just a smidge for a snug, yet secure fit.
Also, look at your metal connectors. You will notice that one of mine has four points whereas the other has five. If both pieces are identical on your setup, this coupler will not work.