Just Buy a Good Knife
Slicing up a watermelon is not as complicated a task as gutting a pig. You don’t need any specialized tools for the job, and especially not a rolling step cutter contraption that promises to deliver perfect watermelon cubes. Slicing up a watermelon with a high quality and suitably sharp knife might actually be easier than cutting butter with a hot blade. The knife is also much easier to clean when the task is done, and can handle every last scrap of the watermelon. Waste not, want not.
