20mm calibration cube with hole 10mm

thingiverse

I'm using Cura settings because that's all I have available to me. This calibration is necessary for both outside walls and inside walls. If the inner hole isn't exactly 10mm in size, you'll need to adjust your Cura setting: Go to Print setup - Custom - Shell - Horizontal Expansion. To calculate the correct setting, follow this formula: Divide the difference between the measured value and 10mm by two.