That's it then, your email address has been noted.
I find Amazon the worst for sending items you may be interested in after taking a peek at something.
Believe it is not so bad on these as it would be on others as the floor goes in first with bulkheads afterwards plus no sliding roof helps.
Apologises if Im wrong.
The key is the drive point not the taper as seen by the condition of the coupling keyway.
What is the threaded section for?
Agree, I have made custom keys where one part is bigger than the other to suit shaft and coupling.