Had some difficulty making the juice groove on a round cutting board, until I came up with fixture shown in photo, which uses a router, and two ball bearings to guide the cutting board.
Arrow on fixture shows direction to rotate the cutting board so that spinning router bit does not push it away from the ball bearings.
IMG_6092.jpg
Fixture in use:
https://youtu.be/KY2SxAENL88?t=85