Quote Originally Posted by 3dNoob View Post
"Don't forget to re-level the X idler"

Can you clarify this? Wondering if I missed a step in the build instructions
Even though the two Z steppers receive duplicate instructions from the driver board and they should be in sync, there are some situations when one can wind up lower or higher than the other:
- Powering off while the Z drive is running
- Loosened clear plastic coupling between the Z stepper and the threaded rod (hence the Zip tie or $10 coupling OME mentioned) -- This is the most common reason for Z stepper disparency
- Rapidly moving one stepper motor (like the X or Y) when the unit is off can generate current in the system and make other stepper motors and fans move (I've even moved the Y motor and powered up the RAMPS once). This current can move one of the Z steppers and not the other.

Easy fix - Make sure the unit is turned off. Next, I make sure my Z steppers are attached SOLIDLY to the threaded rods (I use Zip ties around the clear plastic). Then I get a small bubble level and make sure the whole frame is level (check the top of the frame and then the front forward end). Then, I check to make sure the Z idler (the unit the extruder is mounted to) is level as well. If not, I spin the left Z threaded rod until it's level (I'm sure you could use the right side).