How to Machine Internal Threads with G76

Writing G-Code for Internal screw cutting can be a little tricky. Marc from G-code Tutor shows us how it works.

These are a few ways we can create an internal screw thread, we can use G92 or G32, but the most common way is by using G76.

Most modern versions of FANUC use the two line version so this is the version we will focus on. For more information on machining with the single line G76, head over to https://gcodetutor.com/cnc-machine-training/g76-thread-cycle.html to learn more.

Marc starts the video at the bore, giving enough run up in the Z axis to cancel any backlash that might be present in our lead screws.

Each word of the two G76 blocks is described so we understand exactly how the cycle works.

Remember that all G-Code, even from GCodeTutor should not be copied blindly into your program without fully understanding how it all works, this is because each machine is slightly different in the way it handles the code and what works on one machine might not work as expected on another.