The stock Ender 3 uses a simple endstop switch in the Z min position for homing the Z axis. The mount for the switch is adjustable by sliding it up and down the frame. Unfortunately, the Ender 3 bed will often by cupped and cause a dip in the center. When leveling the bed at the corners it may prevent the nozzle from touching the bed at the center.
Removing the Z min endstop mount entirely will allow you to move the nozzle all the way down. Since we're about to install a BLTouch anyway, we may as well remove it.
However, rather than just remove it entirely, we can move it to the top of the frame and use it as a Z max endstop which is useful for resuming after a power loss, since it will be impossible to use the probe to rehome the Z axis while a print object is still on the bed.
Note the orientation of endstop mount as installed at the top of the frame. The switch will be triggered when the X axis extruder arm reaches the top. This may limit the amount of Z axis travel, but due to the bowden tube, and wiring harness, this is really the maximum viable travel anyway.
You'll need to extend the endstop wiring. I was able to tuck the wire into the frame extrusion underneath the wheel. I used a small piece of electrical tape to hold it in place. The other end of the wire extender plugs into the stock Z endstop wiring.
In my case I had a length of wire used for optical endstops that matched the plugs of the Ender 3. If you don't have something similar you may need to cut the plugs and re-crimp new ones.
Next we will change the config.g and homez.g to reflect the new endstop position.
Your contributions are licensed under the open source Creative Commons license.
Insert a new line below
Insert a new line above
Indent current line
Unindent current line
Delete current line
Navigate to next step.
Navigate to previous step.