My setup has been down the last two weeks for issues not related to my table. After getting it back up and running I was jogging the different axes and realized the z wasn’t moving. Before the down time I was not having any issues what so ever.
I looked in and could see the lead screw and the coupler were both motionless, looked at the top of the z-axis motor and could see the shaft rotating freely. This kinda confused me since the z was at the top of its travel and I would have thought it would at least drive down without slipping since it had obviously had enough grip before to move up and down without apparent issue. But no, nothing but the motor shaft was moving.
Lucky for me the coupler was positioned such that I could tighten the screws, of which the two top cap screws moved easily making me think they weren’t very tight to begin with.
Since the z-axis assembly came assembled I didn’t even think to check the coupler, but you know what happens when you assume anything.
So just a reminder to check all the fasteners, even (or maybe especially) the ones you didn’t install.