Shuffling Magnets

For an experiment, I have to place magnets onto a rectangular board whose dimensions are 3 and 3.5 inches. Between each phase of the experiment, I have to shuffle these magnets around, but if two magnets get within 1 inch of each other, they’ll stick together, and trying to separate magnets as strong as the ones I have is a real hassle.
How many magnets can I place on a board such that I can switch any two without any sticking together? Other magnets can move, but they have to return to their original positions after the two are swapped.