It took me a week to execute a simple task. Referring back to the interference fit for the Z axis screw, my planned fix involved cleaning the threads on both parts and filing down the folded thread on the screw.
My initial mock up here, in which I've placed a knife in the channel between threads to act as a protective barrier between my filing work and good threads, proved cumbersome. In the end I simply held the file as I would a pencil and exerted more care than slop.
Success! Sometimes the fastest fixes are the most satisfying.
Next phase of the CNC project entails getting metal milled for the gantry. Once the gantry is solidly defined I'll build the frame on which it connects to the table, most likely out of wood since my budget is wearing thin. I reason that the framework is a bolt in layer, that can be upgraded if wood proves inconsistent in dimension.
It also looks like my initially just hoped for feature of a spindle RPM control for the Porter Cable 75192 fixed speed 3 1/4 HP router motor is achievable with the Super-PID closed loop controller. I think I would have easily burned up more than twice the cost of that trying to engineer something myself.