Z axis endstop for Prusa i3 rework

First of all, sorry for low quality printed parts. My printer is not yet calibrated well for ABS printing.
So this is my design of Z endstop holder.

Top part fits M4 nut and screw. Use only nylon nut because X axis makes vibration which can force screw go down.
Bottom part designed for NEMA 17 motor. Left side of the printer.