Spindle Control G-Codes: M03, M04, and M05 [or M3, M4, M5]

CNCCookbook’s G-Code Tutorial

The spindle control g-codes control when the spindle is spinning and which direction it spins:

• M03:  Start spindle spinning clockwise.
• M04:  Start spindle spinning anti-clockwise.
• M05:  Stop spindle spinning.

Use the S word to control how many rpms the spindle turns at.

Most M03 and M04 g-codes are issued right after the S word establishes the rpm.  For example:

S2000 M03

That g-code will start the spindle running clockwise at 2000 rpm.

Example

Note:  For most g-code dialects, the leading 0 is optional.  You may refer to M03 as M3, M04 as M4, and M05 as M5 gcode.