Ev-technologyHow-ToBeginner · 4 min read

How to Program Chamfer in CNC: Simple Guide with Examples

To program a chamfer in CNC, use G01 linear interpolation with angled moves or G41/G42 tool radius compensation for chamfering tools. Specify the chamfer angle and length by moving the tool along the edges at the correct angle using coordinates or incremental moves.

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Syntax

The basic way to program a chamfer is by using G01 for straight cutting moves at an angle. You specify the end point coordinates to create the chamfer edge. Alternatively, use G41 or G42 for tool radius compensation when using a chamfer tool.

G01 X... Y... Z... F...: Linear move to create chamfer edge
G41/G42 D... : Tool radius compensation left/right
F...: Feed rate for cutting speed

gcode

N10 G90 G00 X0 Y0 Z5
N20 G01 Z-5 F100
N30 G01 X10 Y10 F200  ; chamfer edge move
N40 G00 Z5

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Example

This example shows how to program a 45-degree chamfer on a corner by moving the tool diagonally from (0,0) to (10,10) while lowering the Z-axis to cut the chamfer.

gcode

N10 G90 G00 X0 Y0 Z5
N20 G01 Z-2 F100
N30 G01 X10 Y10 Z-2 F150  ; chamfer cut at 45 degrees
N40 G00 Z5
N50 G00 X0 Y0

Output

Tool moves to start at X0 Y0 Z5 Tool plunges to Z-2 Tool moves diagonally to X10 Y10 Z-2 cutting chamfer Tool retracts to Z5 Tool returns to start

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Common Pitfalls

Common mistakes include:

Not setting the correct feed rate, causing poor surface finish.
Forgetting to use G90 (absolute) or G91 (incremental) mode correctly, leading to wrong tool paths.
Not retracting the tool before rapid moves, risking collisions.
Using wrong tool radius compensation direction (G41 vs G42).

gcode

N10 G91 G01 X10 Y10 F200  ; wrong: incremental mode may cause wrong chamfer
N20 G90 G01 X10 Y10 F200  ; right: absolute mode for correct chamfer

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Quick Reference

Command	Description
G01	Linear interpolation for cutting moves
G00	Rapid positioning (non-cutting)
G41	Tool radius compensation left
G42	Tool radius compensation right
F	Feed rate (cutting speed)
G90	Absolute positioning mode
G91	Incremental positioning mode

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Key Takeaways

Use G01 with angled moves to program chamfers precisely.

Set correct feed rates and positioning modes to avoid errors.

Tool radius compensation (G41/G42) helps when using chamfer tools.

Always retract the tool safely before rapid moves.

Double-check coordinate mode (absolute vs incremental) for correct paths.