You don't really need "limit" switches with steppers. Weld or bolt a mechanical stop to the ends of your table so the gantry cannot take a flying leap off the table if you manage to mess up. Using steppers that way and stalling will not hurt the motors.
Home switches are a means so the table can find known locations and use them as 0,0. Unless your gantry is in a bind when it is squared (and it should not be in a bind) it will not move out of square when powered up or down. Really the only time I even use my home switches is if I manage to run over something I have left in the way of the gantry. Like ground leads, tools, gloves etc. Then I "home" the gantry and it squares itself up and you are off and running again.
Hope this helps.