Cutting an arc in the Y/Z Plane

[JoeD (Joe DiCiacco)]

All examples of cutting arcs seem to be in the X Y Plane
If anyone know how to cut an arc in the Y Z plane please let me know.
Goal: to cut two 1/4 slots in the back of a guitar neck for strength.
The guitar neck is aligned in the Y direction with frets facing down on machine
The guitar neck changes angle to 17 degrees and rises up in the Z plane (tuning pegs mounted here)

I am trying to cut an arc in the Y Z plane that is 4 inches long
The height of the Arc is .0955 inches
Using the calculator, I get a 20.99016 inch radius at 11 degrees

The code below is for linear motion - it is close to what I need
but as you can see it is not a curve

G90 ;absolute positioning
G20 ;inches
G0X1.0Y1.00Z0.070 ;move to starting point
G1Z-0.05F8.0;lower the bit down from zero for first pass
Y1.50; start here
Y3.50F8.0; move from starting POINT 2 INCHES at a feed rate of 8
Y5.50Z1.00F8.0; START CLIMB UP THE NECK

any help would be appreciated to know how to program an arc instead of linear motion

[WillAdams (William Adams (Carbide 3D))]

In theory one could program G2/G3 arcs to do this by hand — in practice, it’s tedious beyond reason since Grbl doesn’t support loops and variables.

There are a number of programmatic tools:

https://wiki.shapeoko.com/index.php/Programming

I tried to do this sort of thing using OpenSCAD and was scolded for creating objects with untold numbers of triangles which brought the program to a standstill.

A bit more workable option would be to model the neck in Carbide Create’s Pro 3D modeling mode which is currently free for 1 yr.:

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Or, use a more conventional 3D CAD and CAM toolstack: https://wiki.shapeoko.com/index.php/Online_resources#Guitars

[fenrus (Arjan van de Ven)]

the other thing one can do is use my (somewhat new) tool where you can “fold” any Cabide Create generated GCODE over a surface as specified by an STL tile… (but it does not support g2/g3 arcs yet… I need examples to test for that)

see Test cuts with the newly installed spindle