Before using a code: this is a learning reference, not a machine-ready program. Verify the exact controller manual, setup, tools and offsets; simulate and complete a supervised prove-out.
Choose what you want to understand.
G & M codes
Find a code and its milling or turning meaning.
Open the guide → 02Milling cycles
Drilling, pecking, tapping, boring and pockets.
Open the guide → 03Turning cycles
Roughing, finishing, grooves and threads.
Open the guide → 04Control & program words
Screens, operating modes and program address words.
Open the guide → 05GD&T symbols
Symbols, datums, tolerance zones and drawing reading.
Open the guide →A useful order for beginners
- Start with units, axes and the active work origin.
- Read the G/M code and the words that give it values.
- Choose the cycle from the feature: hole, bore, groove or thread.
- Read the drawing requirement and plan how to inspect it.
- Simulate the verified program and practise with an instructor.
Is there one complete list for every CNC?
No. Codes vary between manufacturers, milling and turning, control series and installed options. This reference explains widely used concepts and clearly labelled Haas examples. Additional functions depend on the machine. FANUC code systems and Siemens cycles need their own manuals; a similar code number is not proof of compatibility.
Learn it with an NC4U example
Start with a feature on a component: a hole, a pocket, a groove or a thread. Identify what the tool must do, choose a suitable cycle, then check the tool, offsets and clearance. Our diagrams explain the idea; the exact machine manual determines the supported syntax.
NC4U Solutions · Original learning notes and illustrations · Updated 9 November 2026.
Turn this knowledge into a practical skill.
Learn CNC setting, manual programming and Mastercam with NC4U in Coimbatore or Chennai, or join online from anywhere in India and worldwide. Discuss your current experience and preferred training language.