Reply by a1Jim

Ditto on Loren’s input
You might want to play with the feed rate to see if that helps. Learning how to change the sand paper is essential .
As I’m sure you know end end grain is much tough to sand. To get your cutting boards flat you may want to start with even more coarse sand paper 36 grit if available . As with any sanding you have to work your way through the grits to get the kind of finish you want.

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/