Here is a small part that twists into the Makerslide rail and rests on the T-nut / set screw (for extra support) that most Ord Bots use for Z-Axis home control. It has a hole for a M5 machine screw that can be "micro-adjusted" for precise, and easy, Z-home setup.

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You can use any screw you like, you only need to adjust the hole diameter in Blender or the STL editor ofyour choice. After that:

1) Print with any layer height (shouldn't matter) and middle of the road fill (I used 50%).

2) Home the Z-Axis (to give yourself an idea of a starting point)

3) Lower the height of the T-nut

4) Tap the hole with a M5 screw and then twist part in to place above the T-Nut and roughly where home should be (at the top of the screw head)

5) Slide the T-Nut up beneath the new part and tighten the set screw

6) Adjust home to your liking by turning the screw in small increments