Fanuc G85 Boring Cycle

G85 boring cycle is used to bore a hole.


G85 X... Y... Z... R... F... K...
XHole position in x-axis.
YHole position in y-axis.
ZDepth, tapping from R-plane to Z-depth.
RPosition of the R plane.
KNumber of cycle repetitions (if required) .

Once given in program G85 boring cycle is repeated at every axis movement until G80 is given in program to end this cycle.


N150 M6 T2
N160 G90 G00 X60 Y28 Z12 S100 M03
N170 G99 G85 X60 Y28 Z-15 R2 F120
N180 G98 Y12
N190 G91 G80 G28 X0 Y0 Z0 M05
N200 M30


Brief description of how G85 boring cycle works,

G85 boring cycle working

G85 boring cycle working

1- Rapid traverse to X, Y position.
2- Rapid traverse to R-plane.
3- Boring with feed from R-plane to Z-depth.
4- Retraction with feed from Z-depth to R-plane.
If G99 is given then boring of this hole ends.
5- Rapid traverse to Initial-level only if G98 is given in part-program with G85.

G98 G99 Modes

How G85 boring cycle behaves upon G98 or G99 mode,

G98 Boring tool will return to the Initial level
G99 Boring tool will return to R-plane.

For a working example see G81 drilling cycle.

Repeat Drilling

If K parameter value is given with G85 boring cycle, then boring will repeat the number of times given with K. See G81 drilling cycle example.