Tertiary crushers are used to produce sand from medium-hard stones. In tertiary crushers all sides of the breaker plates can be utilized. When one side of the plate has corroded, the machine rotates the rotor conversely so that other side of the plate does the crushing. When both sides of the plate are worn it is turned upside down so that other two sides can carry out the process. Primary crushing is realized when stones entering into the machine hit plates on the rotor. Then such stones are transformed into sand upon hitting the flappers. Machines of differing capacities can be manufactured depending on customer demands.