I think a good start would be to just draw a 1"x3"x 28" rectangle.
Then what I can figure out us to place a 12" radii on both ends and gave a ball mill make that entire board have a 12" radii across the. 3" width.
After that, I can place the fret position and figure out how to keep the end mill down to follow the radii and stay at a consistent depth.
Thus a Fret Board is made.


Sent from my iPhone using Tapatalk