Here are some steps you can take to locate and fix the bind:
- The lead screw may be dry. Lubricate with machine oil and jog the machine to ensure that lubricant also gets into the threading of the lead nuts.
- The motor coupler may be loose, not properly gripping the lead screw threading. Try tightening the set screws in the motor coupler until they cannot be tightened any more.
- The motor or bearing mounts may be out of square, causing a slight flex in the lead screw. Visually inspect that the mounts are mounted onto the gantry rails as square as possible, using a protractor if necessary.
- The lead screw may be bent. Uninstall the lead screw and check it for a bend by rolling the lead screws along a clean, flat surface. If you identify a bend, try to straighten it by using light hand force.
- The lead nut might be improperly installed on the lead screw. Uninstall the lead screw from the machine, then uninstall the lead nut from the lead screw. Compress the spring on the lead nut to fully open it, and keep the spring compressed while you install it onto the lead screw.
- The lead nut mount may be out of square. This is an extremely rare issue, and you can identify it by loosening the four bolts and nuts that mount the lead nut until the lead nut can be wiggled around by hand. Once the lead nut is mounted slightly loose, attempt to jog the machine.
- The motor port or the pins in the motor plug might have arc damage. This is also an extremely rare issue, and is usually caused by either not using the thumbscrews on the motor plug or by motor plug thumbscrews that are too long. Check for any signs of arc damage to the motor port or he pins in the motor plug. If you notice any damage, please send pictures of the damage to firstname.lastname@example.org