My aim was to fit limit switches to all three axies and my main aim was to keep them as far from the oil and swarf as possible. This has only partially been completed. the x and y switches are in place but not wired up. i actually do not think they are really needed. the main bed is strong and over travel just results in stalled motors. so i have yet to connect them up to the main PC.
For the Y axis , I bolted a steel bar to the moving part which entered a hole in the rear compartment. Here two limit switches could be positioned well away from all the oil etc.