Just a simple way to mount an endstop switch to a linear rail. 

-Tested with voxelab aquila and Geeetech A10

-Switch pcb screw spacing 14mm c/c

-Print a little spacer if you need it. file below

Print an M3 t-nut if you dont have one: https://www.printables.com/model/129445-t-nut-m3-for-alu-2020-v-slot