When I'm working with a hatchet I always chop a few quick notches into the wood down the belly of the stave to act as stoppers---when my hatchet hits those stoppers it only takes out the wood above the stopper, and can't tear out the grain because the grain is cut there. Now, this only works for when you don't have to worry about thickness too much, and you gotta be careful about how deep you make the notches , but it is the best way I know of to prevent tear-outs with a hatchet.