Haas Lathe · G-code
G41 Tool Nose Compensation Left
Compensates for insert nose radius so tapers and arcs are cut to size. G41 left, G42 right of the path.
What G41 does on a Haas lathe
Lathe inserts have a nose radius, so a profile programmed to the theoretical sharp point leaves tapers and arcs undersize or oversize. Tool nose compensation corrects that using the radius and tip direction entered on the tool offset page.
For a typical OD turning tool travelling towards the chuck, G42 is used; for boring towards the chuck, G41. Turn it on during a linear approach move and cancel it with G40 on the way out.
G41 format
| Address | Meaning |
|---|---|
G41 / G42 | Comp left / right of the path |
G40 | Cancel |
Offset page | Nose radius and tip direction for the tool |
G41 example program
G00 X2.1 Z0.1
G42 G01 X0.75 Z0.05 F0.01 (comp on during approach)
Z-1.
X1.5 Z-1.5
G40 G00 X2.5⚠ Watch out
A wrong tip direction number on the offset page is the silent killer — the program runs fine but every taper and radius is off.
Related codes
G41 questions
Do I need tool nose comp on a lathe?
For straight turning and facing the error is zero. For tapers, chamfers and radii, yes — otherwise they will be out of size.
Independent reference. Not affiliated with, sponsored by or endorsed by Haas Automation, Inc. Haas is a trademark of its respective owner. Always confirm codes against your machine's operator manual — options and settings vary by model and software version.