G Code for Turning Straight: Syntax and Example

To turn a straight line on a CNC lathe, use G01 for linear interpolation combined with coordinate values for the tool path. The command moves the tool in a straight line at a controlled feed rate, essential for straight turning operations.

Syntax

The basic syntax for straight turning uses the G01 command, which tells the machine to move the tool in a straight line at a set feed rate.

• G01: Linear interpolation (straight line move)
• X: Target position along the X-axis (diameter or radius)
• Z: Target position along the Z-axis (lengthwise along the part)
• F: Feed rate (how fast the tool moves)

Example: G01 X20 Z-50 F0.2 moves the tool straight to X=20 and Z=-50 at feed 0.2.

gcode

G01 X20 Z-50 F0.2

Example

This example shows a simple straight turning move from the current position to X=30 and Z=-100 at a feed rate of 0.15 mm/rev.

gcode

N10 G90 G95 G54
N20 T0101 M06
N30 S1200 M03
N40 G00 X50 Z5
N50 G01 X30 Z-100 F0.15
N60 G00 X100 Z100
N70 M05
N80 M30

Output

Tool moves rapidly to X50 Z5, then cuts straight to X30 Z-100 at feed 0.15, then retracts.

Common Pitfalls

Common mistakes when programming straight turning include:

• Forgetting to set the feed rate with F, causing the machine to use rapid moves which can damage the tool or part.
• Using G00 (rapid move) instead of G01 for cutting moves.
• Not specifying both X and Z coordinates, leading to unintended tool paths.

Correct usage ensures smooth, controlled straight cuts.

gcode

Wrong: G00 X20 Z-50  (rapid move, no cutting)
Right: G01 X20 Z-50 F0.2  (controlled straight cut)

Quick Reference

Command	Description
G00	Rapid positioning (non-cutting move)
G01	Linear interpolation (straight cutting move)
X	Target position on X-axis (diameter/radius)
Z	Target position on Z-axis (lengthwise)
F	Feed rate (speed of cutting)

Key Takeaways

Use G01 with X, Z, and F to program straight turning moves.

Always set a proper feed rate with F to avoid rapid moves during cutting.

Avoid using G00 for cutting; it is for rapid, non-cutting moves only.

Specify both X and Z coordinates to control the tool path precisely.

Check your program for correct command sequence to prevent tool or part damage.