# LinuxCNC G86

Instructions · `G86` · verification: source checked

G86 is a LinuxCNC canned boring cycle. It feeds the Z axis to the programmed depth, dwells for P seconds, stops the selected spindle, rapid-retracts to clear Z, then restarts the spindle in its previous direction.

## Specification

| Property | Value |
|---|---|
| Language | gcode |
| Code | G86 |
| Group | canned cycles |
| Syntax | G86 (X- Y- Z-) or (U- V- W-) R- L- P- $- |
| Dialect | LinuxCNC |

### Parameters

| Name | Description |
|---|---|
| X | Axis word from the XYZ group; used when the active plane requires XYZ. |
| Y | Axis word from the XYZ group; used when the active plane requires XYZ. |
| Z | Axis word from the XYZ group; used when the active plane requires XYZ. |
| U | Axis word from the UVW group; used when the active plane requires UVW. |
| V | Axis word from the UVW group; used when the active plane requires UVW. |
| W | Axis word from the UVW group; used when the active plane requires UVW. |
| R | Retract position along the axis perpendicular to the selected plane. |
| L | Number of repeats; optional, and L=0 is not allowed. |
| P | Dwell time in seconds. |
| $ | Selected spindle; chooses which spindle is stopped. |

## Safety

- The spindle must be turning before G86 is executed; otherwise LinuxCNC reports an error.

## Study notes

- G86 is a boring canned cycle that uses a P number for the number of seconds to dwell.
- Sequence: feed the Z axis to the Z position, dwell for P seconds, stop the selected spindle, rapid move to clear Z, then restart the spindle in the direction it was going.
- Preliminary and in-between motion is shared with other canned cycles in the G80-G89 family.
- Canned cycles use X Y Z or U V W depending on the active plane; rotary axis words are not allowed in canned cycles.
- G80 or another modal group 1 G-code cancels a canned cycle.

## Sources

1. [G-Codes](https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g86) (accessed 2026-10-26)

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Source page: https://machineschema.com/instruction/gcode-g86  
JSON: https://machineschema.com/instruction/gcode-g86.json  
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite Machine Schema and the original sources.