Not yet supported G-Codes (Milling)


Late last year I had a review of the supported milling G-Codes against other systems (Fanuc, Haas, etc) to see what the existing gap in G-Code coverage. The resulting list of differences was compared against requests on this forum to determine what is actually required by end users. The following are the resulting groups of G-Codes based on G-Code order.

Cutter Compensation
  • G40 - Cutter compensation Cancel
  • G41 - Cutter compensation Left
  • G42 - Cutter compensation Right

Notes / Opinion: Probably the most urgently required G-Code group as this is useful for jobs chasing tolerances of a thousandth of an inch or less. This allows for adjustment based on tool wear without needing to regenerate the job from the CAM package.

Tool Length Offset
  • G43 - Tool Length Offset + Enable
  • G44 - Tool Length Offset - Enable
  • G49 - Tool Length Offset Cancel

Notes / Opinion: My reading of the G-Code implementation is this updates the tool offsets table from within the job program. If automatic tool length calibration is configured then these G-Codes are redundant for a Masso Controller

Coordinate System Rotation
  • G68 - Coordinate System Rotation
  • G69 - Coordinate System Rotation Cancel

Notes / Opinion: Nice to have but not essential. CAM packages can perform rotation and generate final co-ordinates.

  • G84 - Tapping (including rigid tapping variants)

Notes / Opinion: Unless the mill has a servo motor on the spindle this will be technically impossible to implement. The issue is the necessary degree of precision of the spindle rotary encoder, for example cutting a 2 mm pitch thread with a spindle having 0.01 mm end play requires a rotary encoder with > 200 divisions/revolution. High count rotary encoders then run into the problem that the input processing speed.


Hi all, new member, no cnc machine yet.

Very surprised to learn that cutter compensation is not supported, and this may affect my purchase decision when it comes to choosing a controller. I have used cnc machines enough to know how important cutter compensation is, and wish to add my support to requesting the adoption of the G-codes listed above.

Regards, Ian.



For any of the feature requests please click the "thumbs up" for the original posting in the thread to vote for the item.

This is mentioned in the description of the "Feature Request" forum but most people miss it.