Z Axis does not move up or down (Solved - Delrin nut screwed on too tight)

Let me first say thank you to all of you. I have learned much reading here and on FB.

I’ll give the problem and the solution.

Problem. After assembling the x-carve (1000), during the check to test the wiring, the z axis did not work. The motor was trying to turn the leadscrew and I could turn the leadscrew with a wrench. But the motor attached with the pulley did not turn the leadscrew.

Solution. The 25280-03 Delrin Nut ACME 3/8-12 was binding the leadscrew. I had the 2 25286-45 Button Head Cap Screws M5 × 16mm too tight. I loosened them both a little tried the motor and the leadscrew turned! So I have to leave them slightly looser than my normal torque setting of goodandtight. On to carving!