Proper calibration of the printer's x, y, and z axes is important if we want an accurate reproduction of a model. This includes both the physical alignment of the axes to each other and the calibration of the firmware, which provides instructions to the stepper motors that drive the axis. For this recipe, we'll assume that you have a 3D printer that's well constructed and has aligned axes. What we'll focus on is finding the correct firmware values for your x, y, and z axes.
You'll need a precision caliper or, at the very least, a metric ruler for this recipe. You'll also need your current E_steps_per_unit value, which is located in your firmware settings in the Configuration.h file. If your firmware allows, use a M503 command to echo your printer settings. What you are looking for are two lines similar to the following:
echo: Steps per unit: echo: M92 X90.00 Y90.00 Z4160.00 E989.00
The values you need will be listed after the axis. In this case...