Home › G-codes › Hurco WinMax (NC) › G87

G87 Back bore (ISNC) or chip breaker (BNC)

Hurco WinMax (NC) G-code · Mill

ISNC: back boring, the tool goes down through the hole shifted, moves on center and bores up. BNC: chip breaker drilling with a dwell every .050 inch.

Format

ISNC: G87 X Y Z R {Q or I J} [P] F

Addresses

Address	What it does
`X Y`	Hole position
`Z`	Top of the back bore, the end point
`R`	Depth reached before shifting back on center
`Q or I J`	Bore shift. Q uses the machine direction
`P`	Dwell
`F`	Feed rate

How it works

Modal, group 09. Cancel with G80.

Example program

T10 M06 (BACK BORE BAR)
G90 G54 G00 X2. Y2. S800 M03 (HOLE CENTER)
G43 H10 Z1. M08 (LENGTH OFFSET)
G98 G87 Z-.5 R-1.1 Q.1 F3. (BACK BORE UP TO Z-.5)
…

The full 5-line example is in the app. Example is in inch. Check offsets and clearances first.

Watch out for

Check that the shifted tool clears the hole on the way down. Orient and shift direction come from machine setup.
BNC G87 dwells two spindle turns every .050 inch to break the chip. Feed only, no full retract.

Related codes

G76 · G83 · G80

G87 on other controls

The same number can mean something different on another control.

Control	Meaning
Fanuc	Back boring cycle
Haas NGC	Boring cycle, stop and manual retract
Mazak (EIA)	Side drilling cycle, live tool
Okuma OSP	Back boring cycle
Mitsubishi M70 M80	Back boring cycle
Brother Speedio	Back boring cycle
Fagor 8055 8065	Rectangular pocket canned cycle
LinuxCNC Tormach	Back boring cycle, not implemented
Mach3 Mach4	Back boring
Fadal	Bore in and out, Fadal G87
Swiss (Citizen Star)	Side drilling cycle

Every G-code for Hurco WinMax (NC) in your pocket. The app has the full example programs, search by number or shop word, a line decoder and calculators for tapping, threading and drilling.

Open G87 in the app All Hurco WinMax G-codes

App Store Google Play