Code reference
G20 vs G21: Inch vs Metric in G-Code, Explained
G20 tells the control to read the program in inches and G21 in millimeters. Here is the difference, why the wrong one is dangerous, and how to keep them straight.
Lawrence Arya··4 min
Practice
Why Is My CNC Moving in Inches Instead of MM? Fix It
A CNC moving in inches when you expect millimeters is running G20: left active by a previous job, a power-on default, or a program that never states units.
Lawrence Arya··4 min