Update 5/27/2019: Here is the endstop/limit switch cover that I used that goes well with this part: https://www.thingiverse.com/thing:3394736

UPDATE: 3/3/2019: Uploaded V3 of this part which should fit Early Ender3's with longer stepper shafts and pulleys with grub screws (ie, not press fit).

UPDATE: 2/2/2019: V2 of this part fit for those with press-fit pulleys and more recent Ender3s with shorter stepper shafts,
But for Older Ender3s with pulleys and grub screws it doesn't give the clearance from the pulley needed to give the full endstop range to allow to print all the way to the X edge of my bed. The stepper motor shaft just slightly interferes.

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I remixed this to expand the space for the solder joints on the back of the board, to make the cutout more symmetrical. It seems like that my specific solder joint on my X endstop switch was positioned lower/differently than oldcrow66's which ended up with interference. It would have worked if I force installed it crooked but that would bug me since it's visible from the front in the printer.

Note that the numbers on the X endstop switches are different between mine and oldcrow's, so Creality likely changed the part. I also notice oldcrow seems to have a press-fit pulley while mine is one of the early Enders with offset wheels and grub screw pulley

Also another difference seems to be that I ran the model through netfabb, and it seemed to have made it slightly smaller, so it's no longer a very tight friction fit into the V-Slot.

Pictures demonstrate what I was attempting to fix with the original part.