Machine a sphere with a groove down the center

[traditional.builds]

Any idea on how to machine the center "slot" of this half sphere? 

I have tried a few different 3D / 5-axis toolpaths to some success, but I was wondering if there was a simpler way to do it?

I am playing with the Multi Axis Extension for another week while I still have the trial and wanted to test out some simple things, to see how I could incorporate it into more intricate jobs.

I used a 2D roughing operation to clear the bulk (assuming it will be cut from a square stock) and then used a 3D spiral with a ball to get the outer sphere shape, I just need help with the center slot. It does not need to be perfect.

Right now, I am not worried about tool/holder collision with the base stock. I am just looking for the appropriate way to machine this. I will deal with stock/collision stuff when it comes to the actual machining.

Thank you in advance!

[dames123]

If you have a 5 axis machine I would use a swarf toolpath on the slot walls.

[programming2C78B]

A multi axis toolpath with a "to point" (center of sphere) direction comes to mind, as well as the advanced swarf like your wavey flag.