The Shapeoko 3 CNC Machine does not come with the mounts necessary to enable the use of End Stops (limit switches) to protect the machine from running its head against itself.
A homing kit is available from the makers of the Shapeoko 3, but it only offers the possibility of homing, it does not deal with "max" limit end stop.
This thing contains 3 parts that can be used to setup homing and maximum limit detection (except Z).
Only the X mount can be printed without support.
I have not included a reversed X mount, but that is pretty easy to flip the existing one.