adjust. min/max endstops for Z-axis

- mount for endstops, adjustable for the min. endstop
- mount for microswitch with wings to prevent accidental disturbing of its position (rotating around sliding rod)
- bolt tip to give a bit of room for deviations
Everything designed for my Prusa i3 (Hesine).

I prefer to use lock nuts (DIN985) in this vibrating environment, so there is room (a tight fit) for the M3-one in the adjuster-screw-block. If you don't have one at hand you can use a normal one plus one at the top of that block to