There are a number of reasons why a steak might be tough. Certain cuts, like flank steak, are inherently tough. These cuts can be made more tender by marinating them, and by slicing them against the grain.
Another common cause of tough steak is overcooking. We suggest you invest in a quality meat thermometer and cook the steak only long enough to reach the desired state (rare, medium, well-done).
Please check back with us from time to time. Technology is always advancing, and alternate solutions arise every day.