Horizontal expansion calibration tool

[EDIT] I've uploaded a more recent version here[/EDIT]

In an ideal world, if you print a 10 mm hole and a 10 mm post, the post would fit into the hole. In practise, some inaccuracy is present. In my experience this often shows up as horizontal expansion (HE) of whatever you are printing - a bit of lateral expansion of the plastic during extrusion makes the wall slightly thicker than ideal.

You can correct for this using the "Horizontal Expansion" setting (under "Shell") in Cura. This print is designed to identify what that value should be set to. If you determine your printer is delivering a positive HE, set a negative one to cancel that out, and vice versa.

The post tapers from 10 mm diameter to 9 mm diameter over a length of 20 mm. There are 1 mm gradations along the length (barely visible in the photo on the right, you could fill them with ink if you wanted to increase contrast). The block contains a hole that theoretically perfectly fits the post.

Assuming your printer