Prusa i3 Z-axis + lead screw combo support brackets

Stabilizes the Z-axis and keeps the Z lead screw nice and straight. This upgrade has definitely improved the prints on my Prusa i3. Uses M8 threaded rods just like the rest of the printer. 2 front rods at 400mm long. 2 vertical support rods at 450mm. You will need to mirror the top support for the left side.