M4 Spindle on counterclockwise

Siemens 840D 828D M-code · Mill and lathe

Starts the master spindle counterclockwise at the programmed S. Used for left hand tools and on many lathes for turning with the insert upside down or rear tool posts.

Format

S M4

Addresses

Address	What it does
`S`	Spindle speed in rpm, or cutting speed in G96

How it works

Modal until M3, M5 or M19.

Example program

T1 D1 ; TURNING TOOL
G96 S200 LIMS=2500 M4 ; SPINDLE CCW
G0 X52 Z2

Example is in inch. Check offsets and clearances first.

Watch out for

For a second spindle write the spindle number, for example M2=3 for spindle 2 clockwise.
Check tool hand before using M4. A right hand tool run backwards rubs and breaks.

Machine builders set many M codes, and they change by model and options. Check the M code list for your machine.

Related codes

M3 · M5

M4 on other controls

The same number can mean something different on another control.

Control	Meaning
Fanuc	Spindle on, reverse
Haas NGC	Spindle on counterclockwise
Doosan (Fanuc)	Left spindle reverse rotation
DMG Mori MAPPS (Fanuc)	Spindle start(reverse)
Mazak (EIA)	Spindle reverse rotation
Okuma OSP	Spindle counter clockwise (Lathes & Mills)
Mitsubishi M70 M80	Spindle on counterclockwise
Brother Speedio	Spindle on counterclockwise
Heidenhain TNC (ISO)	Spindle on counterclockwise
Fagor 8055 8065	Spindle counterclockwise
LinuxCNC Tormach	Spindle counterclockwise
Mach3 Mach4	Spindle on counterclockwise
Centroid CNC12 Acorn	Spindle on counterclockwise
Hurco WinMax (NC)	Spindle on counterclockwise
Fadal	Spindle on counterclockwise
Swiss (Citizen Star)	Main spindle reverse

Every M-code for Siemens 840D 828D 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 M4 in the app All Siemens 840D 828D M-codes

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