DIY Coupling: A coupler for the motor and lead screw (from Marc K.)
This creative coupling solution comes from another generous user of the site. He has devised a way to couple the motor to the leadscrew with standard aluminum tubing. Marc has graciously allowed me to show you this creative idea.

Diagnosing and Fixing a Non-working Axis
Are you pulling your hair out trying to solve issues with your CNC machine? Maybe the X-axis has decided to play hard to get? Don't fret. In this video, I'll walk you through the intricate maze of CNC electronics, from transformers and drivers to contactors and controllers. We'll diagnose a real-world problem with the X-axis of a CNC machine, using nothing but methodical testing and common sense. So, grab your multimeter and let's turn that blinking error light into a green light of glory.

Step 16: X-Axis Lead Screw
This tutorial is dated, if you are considering a CNC for your personal use, we would highly recommend purchasing a kit that is very stable from our wide range of machines available. Instead of using allthread for the lead screw and a standard nut, consider using a 5 start lead screw and anti-backlash nut. It will keep you from pulling out your hair by running much smoother and faster. The y-screw has been installed. The x-screw is now needed. Assembly and concept for the x-screw is the same as the y-screw. The only difference is that you will need to pick up the entire machine and provide access to the bottom.