CNC TRUECUT / MACHINING REFERENCE
G-code and M-code: CNC programming reference
A compact starting reference for common milling motion, feed and machine functions, with links to the control manufacturer’s manual.
Common motion and plane concepts
G00 commonly commands rapid positioning and G01 a feed-controlled straight move. G02 and G03 commonly select circular interpolation, whose direction depends on the active plane and viewing convention. G17, G18 and G19 commonly select XY, XZ and YZ planes. Interpret arcs using the exact control’s centre and radius conventions.
Coordinates, units and feed mode
G90 commonly selects absolute coordinates and G91 incremental coordinates. G20 and G21 commonly select inch and metric units. Feed-per-minute and feed-per-revolution commands vary by control and application. On some controls, codes used for milling cycles have different meanings in turning. Check the active mode before using a calculated feed value.
Machine functions
M03 and M04 commonly select spindle direction; M05 stops the spindle. M08 and M09 commonly control coolant. M06 is commonly associated with tool change on a machining centre, while turning machines may use another sequence. M30 commonly ends a program with reset behaviour. Machine-builder options can change auxiliary functions.
Use a control-specific reference
This page is a conceptual guide, not an executable program or universal code list. Tool offsets, compensation, cycles, safe approach and recovery require the machine’s documentation. Use the official Haas milling manual for Haas examples, or your own control manufacturer’s manual.