Limit switch problem

[JAZZCNC]

Clive is spot on correct regards limits and soft limits it's a dangerorus combination really best avoided which isn't difficult to do.

Regards the Z aixs lower limit then he's not quite correct but still he's right. You won't have to move the switch every time you change tool etc if just protecting the extents of travel but it's mostly pointless because your never likely to hit the switch because you'll have tool in the spindle and material on the bed 99% of the time.
It's also got high potential for trouble from false trips etc because of all the vibrations and debris that get inflicted on Z axis down low.

Better solution is to fit hard stops so the rails bottom and motors stall if for some reason you ever get anywhere near the travel extents. Which is unlikely if your cutting and have anything but really thin material on the bed.

But to answer both your questions of is it do-able then yes it is. Would I advise it 100% NO.

[komatias]

Building on Jazz's note, you can have one switch per axis as long as it is actuated both in both the + and the - direction. But you must have both directions protected! As I said above, the soft limits are only there as a means secondary safety and only work if your machine has homed (Like Clive says)

here is a photo from practicalmachinist forum showing a single roller switch that is actuated by rolls that mount to the face of the table: