LinuxCNC G88 Boring Cycle, Spindle Stop, Manual Out

G88 is listed in the LinuxCNC canned cycle group as a boring cycle that stops the spindle and moves the tool out under manual control. The LinuxCNC documentation states that the code is accepted by the interpreter but is currently unimplemented, so its behavior is undefined. The general canned cycle sections define the common words, sticky words, repeat, retract mode and error conditions that apply to cycles G81 through G89.

Source checked10/10 values · 2026-10-26

Specification

1 source

Language	gcode
Code	G88
Group	canned cycles
Dialect	LinuxCNC

Parameters

Name	Description
X	X-axis word; in canned cycles the X, Y, Z or the U, V, W group is used depending on the selected plane.
Y	Y-axis word; in canned cycles the X, Y, Z or the U, V, W group is used depending on the selected plane.
Z	Z-axis word; the Z number is sticky in the XY plane.
R	Retract position along the axis perpendicular to the selected plane; the R number is always sticky.

Study notes

The quick reference table entry reads "Boring Cycle, Stop, Manual Out (not yet implemented)".
The interpreter accepts G88 but the document defines no motion sequence, retract behavior or word list for it.
Canned cycles are performed with respect to the currently selected plane; any of the nine planes may be selected.
All canned cycles use X, Y, Z or U, V, W groups depending on the plane selected, plus an R word.
Rotary axis words are not allowed in canned cycles.
In the XYZ plane family the UVW axis words are not allowed, and in the UVW family the XYZ axis words are not allowed.
It is an error to use inverse time feed rate or cutter compensation while a canned cycle is active.
It is an error to use an L number that does not evaluate to a positive integer, or to use a required negative P number.
Sticky words keep their value across successive lines of the same cycle; the R number is always sticky and the L number is not.
Retract height is set by G98 (return to the position before the cycle series) or G99 (return to the R position).

Safety

The document states that G88 is unimplemented and its behavior is undefined, and gives no operating limits or safety functions for it.