Update: added version for ppl who still have the zstop switch installed
Over time the X axis on my cr-10 gets out of alignment so i designed this guide to make it simple to check and realign. screw them into your extrusion with 2 m4 screws and T-nuts. i leave them on all the time, just slid forward in t he slots so the hot end shroud does not hit them. when i suspect the bed is unlevel i raise the z. move the nozzle to the center. slightly loosen the screws and slide the guide back till it touches the Z frame, then snug the screw.
CAREFULLY lower the z in increments until it gets close to the guides. If it is unlevel, disable steppers and turn one of the z axis rods by hand until it is level. then raise the z axis, losen the screws and slide the guide back away from the frame.
WARNING i am not responsible if you do not move the guides clear before operating machine.
the guides in the photo are a older version with extra screw holes i decided were not useful.
if you think your x is currently uneven print the parts on the y axis to minimize chances of one side of the part being higher than other,