This method of cutting a juice groove in a cutting board uses just a palm router and an edge guide. I love the simplicity of it, as no CNC or complex jig is required!
– palm router – edge guide that fits your router – 3/8" round nose bit – clamps – combination square – cutting board
Attach the round nose bit to your router. You will make multiple shallow passes, so set the depth accordingly. Attach the edge guide to your router as well.
Set the depth of the edge guide to the closest edge of the router bit to 3/4".
Using your combination square set to 3/4", mark that distance on every corner of the board. Make your marks prominent, because this is what you will be looking for while you are routing. You will stop at these marks.
Start by plunging the router with the edge guide flush against the edge. Tilt it to the side, wait for the bit to reach full speed, and slowly lower the router bit into the piece. Slowly route to the right until you meet your marks, then go left until you reach your other marks. Repeat on the remaining 3 sides.