@wmoy Ok, thank you. Also, I appreciate your videos!
I wanted to make a correction to the above, I went back and re-measured using only the mdi interface and digital calipers (also with z-axis dial setter) and found my z-axis backlash is ~0.04mm (meaning my measurements are 0.04mm short when changing directions along the z), and my $102 value is 199.3…
Method:
-Clamped the head of the calipers to the spoilboard (leveled 1.5" HDPE attached to 5/8" ATP5 aluminum plate base)
-The moveable jaw of the calipers rested on the top surface of the spindle mount ~5mm from the abutment with the Z-axis plate
-Lowered the spindle mount towards the bottom end of the Z-height range (-2mm past what would be zero)
-Jogged up 2mm (2 times press the 1mm increment)
-Zero both the Z-axis in the Jog window as well as the digital calipers
-On MDI tab input typed in “g1 z50 f200”
-Noted that everything reported movement of 50.00mm (both calipers and Carbide Motion 521)
-On MDI tab input typed in “g1 z0 f200”
-After Z-axis motion completed, very carefully pushed the caliper jaw down to rest on surface of spindle mount
-Noted the digital calipers now reported height of 0.04mm, this is the backlash.
This was repeated 4 times, every time the same (with $102=199.3 for my Z-Plus).
Should I be concerned about 0.04mm backlash? What would be outside of margin of error for you?