The mode of a two-mass cone crusher at the approaches to one of the Sommerfeld thresholds is considered. Frequency close to this threshold from low side provides the most efficient energy transfer from the unbalance to the crusher body. However, the stochastic model of crushing shows the possibility of breakdown such mode even after a very long stay on it. The process can be stabilized by introducing a simple control into the system with an input signal from the unbalance tachometer.