4 Axis Spiral Groove G-Code

I need a clean, ready-to-run G-code program that mills a 26-groove, 22° helical pattern into a steel shaft. The blank measures 2.100" in diameter and 1.375" long. I will be cutting on a 4-axis mill with a 1/8" end mill, running 2 IPM feed at 2000 RPM. Target depth is .180", broken up into .060" passes.

I do not have a CAD model; the code will have to rely on the dimensions above. Toolpath must respect the full helix, maintain constant engagement, and leave no dwell marks on entry or exit. Please include clear comments for:

• work-piece zero definition
• tool length and diameter offsets
• each pass depth and helix pitch calculation

Deliverables:
1. The G-code file (.nc or .tap) compatible with standard Fanuc-style controllers.
2. A brief setup note so I can verify axis orientation and safe Z.
3. Optional simulation screenshot or back-plot proving the 26 distinct grooves.

Once the code posts cleanly and the back-plot shows no collisions, we are done.