MPSM Beefier Z-axis tapered coupler

I managed to snap one of the nuts on my original, and I didn't really like how you had to crank on both in order to tighten either. So I stretched it out and added a hex nut on the coupler itself and beefed up both nuts.

There is an extended hole inside on the side for the threaded rod that allows it to go all the way though, instead of lifting the rod up into the extruder motor.

A bit of a brain fart during design of the coupler made the hex not an actual standard size, so it would be be