Horizontal Expansion Test: 0.01mm per 1/10 rotation.

This is yet another test print intended to help set Horizontal Expansion. These are a pair of tapered threaded parts. The pitch (5mm) and taper (4% from c/l) were chosen such that each 1/10 of a turn represents 0.01mm of horizontal expansion. There are marks on the screw and nut and a "perfect" line-line fit will cause the marks to line up and the bottom surfaces to be flush when tightened. The nut is 10 sided, so each corner represents 1/10 of a turn, and thus 0.01mm of horizontal expansion. So, if the bottoms are nearly flush (screw doesn't quite seat), and the screw notch is 2 corners counterclockwise from the nut notch, then the horizontal expansion needs to be brought inward by 0.02mm. If bottoms are over-flush (screw bottom passes nut bottom when tightened), and the screw notch is 3 corners clockwise from the nut notch, then the horizontal expansion needs to be brought outward by 0.03mm. Bonus: turning the screw 1/2 turn counterclockwise from "ideal" is the equivalent to giving a 0.1mm "gap" from a line to line fit in a model. If a printer has been calibrated perfectly such that a 0.1mm gap in the model is a real 0.1mm gap on the print, you can see that the fit (at least over a 10mm shaft) is quite sloppy. Hope this is helpful to someone.