Stone shops run some of the most specialized CNC machines in fabrication: bridge saws that tilt, routers that polish, and hybrids that do both on a slab of granite worth more than the tooling. The G-code question has a reassuring answer and a demanding one. Reassuring: the commands are the standard core. Demanding: stone punishes sloppy habits around those commands faster than almost any material.
Which commands does a stone CNC actually use?
The standard set, exactly as a maintained reference like LinuxCNC’s list documents it:
| Group | Codes | Stone-shop note |
|---|---|---|
| Motion | G00 / G01 / G02 / G03 | Arcs everywhere: sink cutouts, radiused corners, edge profiles |
| Offsets | G54 family | One slab, multiple parts, multiple origins |
| Compensation | G40-G43 | Blade and tool diameters are large; comp errors are visible errors |
| Coolant | M08 / M09 | Not optional. Water is tooling life and dust control |
| Spindle / flow | M03 / M05, M00 / M30 | Standard |
If you can already read a milling program, you can read a stone program today. The learning curve lives elsewhere.
What does stone change about how the commands are used?
Four habits, all non-negotiable. Water is a rule, not a preference: diamond tooling cuts by abrasion and a dry diamond segment overheats and strips in seconds, so the M08 block is effectively part of the safety system, and programs are read with the question “is coolant on before any engagement?” the way metal programs are read for rapid height. Feeds are conservative and material-specific: granite, marble, and engineered quartz behave differently, and the chip-load mindset from the feed rate guide applies with stone-specific numbers from tooling suppliers. Arcs do heavy lifting: a kitchen countertop program is largely G02/G03 around cutouts and edges, so arc-reading fluency pays daily. Engagement is gentle: plunges and entries are ramped or pre-drilled, because stone chips at edges and a chipped slab is scrap with no rework.
Where is the machine-specific layer?
Thicker than usual, and owned entirely by the builder’s documentation. Stone machines mix saw and router personalities: blade selection and rotation, tilt axes for miter cuts on a bridge saw, tool changers carrying polishing wheels in graded sequence, water circuits with multiple zones. The M-codes and cycles for all of that are machine-specific, and the only honest instruction is the one this site repeats for every builder layer: read the manual for your machine and never test an unknown M-code with a slab on the table. The cutting-physics cousin of stone work, waterjet machining, shares the same pattern: standard motion core, specialized everything-else.
How do you prepare for stone CNC work?
In the same two layers as every machine class. The shared code core goes to reflex first, in free 60-second drills with G-Code Sprint auto-repeating misses, on the G-code practice page; the arc-heavy nature of stone paths makes the G02/G03 pair worth extra rounds. Then reading practice on real programs: narrate a countertop program aloud, and at every engagement ask the stone questions (is water on, is the entry ramped, which origin is active for this part of the slab?). The machine-specific layer comes last and on site: the shop’s machines, the supplier’s tooling charts, and supervised slab time, where the router-class learning route habits transfer directly to stone routers.
Bottom line: ordinary commands, unforgiving material
Stone cutting CNC machines speak ordinary G-code, and the search for special stone commands mostly ends at the builder’s manual for the machine layer. What the trade actually demands is discipline around the core: water always on before engagement, conservative material-specific feeds, fluent arc reading, gentle entries. Train the core to reflex, learn the habits deliberately, and let the manual own the rest.
Sources
Frequently asked questions
What G-code commands do stone cutting CNC machines use?
The standard core: G00-G03 motion (arc-heavy in practice), G54-family offsets, G40-G43 compensation, and the familiar M-codes with coolant treated as a hard rule. Machine-specific functions (tilt, blade control, polishing sequences) live in the builder’s manual. To get the shared core to reflex, the free G-Code Sprint app is the top pick: 60-second drills with automatic repetition of missed codes.
Why is coolant such a big deal in stone CNC work?
Because diamond tooling cuts by abrasion and destroys itself in seconds when dry, and because wet cutting controls silica dust. Stone programs are read with “is water on before engagement?” as the first safety question, and shop dust-control procedures are a health requirement, not a preference.
Are feeds and speeds for stone the same as for metal?
No: the arithmetic mindset transfers, the numbers do not. Granite, marble, and engineered stone each get their own conservative parameters from the tooling supplier’s charts, and edge engagement is ramped or pre-drilled because stone chips rather than deforms.
Can a metal machinist move into stone CNC work?
Yes, and faster than most expect: the code core and reading skills transfer fully. What must be learned fresh: water discipline, stone-specific tooling and feeds, slab handling, and the machine’s own layer, all on site under supervision.
G-Code Sprint is a study and practice tool only. Always follow your instructor, employer, machine manual, and shop safety procedures.