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G3 Counterclockwise arc or helix
LinuxCNC Tormach G-code · Mill and lathe
Cuts a counterclockwise arc in the active plane at feed rate. A move on the third axis makes a helix. P sets the number of turns.
Format
G3 X Y [Z] I J [P] F or G3 X Y [Z] R [P] F
Addresses
| Address | What it does |
|---|---|
X Y Z | End point of the arc |
I J K | Center offset from the start point |
R | Arc radius, used instead of I J K |
P | Number of turns, whole number, default 1 |
F | Feed rate |
How it works
Modal, motion group. Stays on until another motion code.
Example program
G20 G17 G40 G49 G54 G80 G90 G94 (INCH, SAFE START)
T1 M6 G43 (.500 END MILL)
S3000 M3
G0 X1 Y0 Z0.1 (START ON THE CIRCLE)
…
T1 M6 G43 (.500 END MILL)
S3000 M3
G0 X1 Y0 Z0.1 (START ON THE CIRCLE)
…
The full 7-line example is in the app. Example is in inch. Check offsets and clearances first.
Watch out for
- I J K are incremental from the start point by default (G91.1). G90.1 makes them absolute.
- P adds full turns. P1 is the default. P3 on a full circle gives three full circles, good for helical thread milling.
- R format cannot make a full circle. Use I J K for full circles.
Related codes
G3 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Fanuc | Circular interpolation counterclockwise |
| Haas NGC | Circular interpolation counterclockwise |
| Mazak (EIA) | Circular interpolation, counterclockwise |
| Okuma OSP | Circular interpolation counterclockwise |
| Mitsubishi M70 M80 | Circular move counterclockwise |
| Brother Speedio | Circular interpolation counterclockwise |
| Siemens 840D 828D | Circular interpolation counterclockwise |
| Heidenhain TNC (ISO) | Counterclockwise arc, Cartesian |
| Fagor 8055 8065 | Counterclockwise circular interpolation |
| Mach3 Mach4 | Counterclockwise arc |
| Centroid CNC12 Acorn | Counterclockwise arc or helix |
| Hurco WinMax (NC) | Circular or helical move counterclockwise |
| Fadal | Circular interpolation counterclockwise |
| Swiss (Citizen Star) | Circular move counterclockwise |
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Open G3 in the app All LinuxCNC Tormach G-codes