# LinuxCNC G84 Right-hand Tapping Cycle, Dwell

Instructions · `G84` · verification: source checked

G84 is a canned cycle for right-hand tapping with a floating chuck and a dwell at the bottom of the hole. The cycle feeds the Z axis to the programmed depth, stops the selected spindle, starts counterclockwise spindle rotation, dwells for the P time, then feeds back to clear Z. It does not use synchronized motion.

## Specification

| Property | Value |
|---|---|
| Language | gcode |
| Code | G84 |
| Group | canned cycles |
| Syntax | G84 (X- Y- Z-) or (U- V- W-) R- L- P- $- F- |
| Dialect | LinuxCNC |

### Parameters

| Name | Description |
|---|---|
| R | Retract position along the Z axis. |
| L | Used in incremental mode; number of times to repeat the cycle. See G81 for examples. |
| P | Dwell time in seconds. |
| $ | Selected spindle. |
| F | Feed rate (spindle speed multiplied by distance traveled per revolution (thread pitch)). |

## Connected

- Related: [LinuxCNC S (Set Spindle Speed)](https://machineschema.com/instruction/word-s.md)

## Safety

- G84 does not use synchronized motion.
- Feed and speed overrides are disabled during the G84 cycle and restored afterward.

## Study notes

- The G84 cycle is intended for tapping with a floating chuck and dwell at the bottom of the hole.
- G84 does not use synchronized motion.
- The dwell length is specified by the P word in the G84 block.
- The feed rate F is spindle speed multiplied by distance per revolution (thread pitch); for example S100 with 1.25 mm per revolution gives F125.
- The cycle disables feed and speed overrides, then restores them to their previous state after the retract move.
- The L word is used in incremental mode as the number of times to repeat the cycle.
- Canned cycles are performed with respect to the currently selected plane; rotary axis words are not allowed in canned cycles.
- Canned cycle axis words are X, Y, Z or U, V, W depending on the selected plane.

## Sources

1. [G-Codes](https://linuxcnc.org/docs/html/gcode/g-code.html#gcode:g84) (accessed 2026-10-26)

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Source page: https://machineschema.com/instruction/gcode-g84  
JSON: https://machineschema.com/instruction/gcode-g84.json  
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite Machine Schema and the original sources.