The wellknown energyefficient method of crushing in a singleroll crushing machine with smooth rolls, in which a complex stress state is created in the destroyed piece, has a significant disadvantage – low productivity due to a limited degree of crushing. In order to increase productivity, singleroll crushing machines are equipped with stop blocks on the roll, which ensure the forced supply of the destroyed material to the crushing zone. The maximum possible number of stop blocks should be installed on the roll, and the condition of guaranteed feeding of the piece into the fracture zone must be met. The developed mathematical model allows one to calculate the maximum possible number of stop blocks, which ensures guaranteed nipping of the original piece into the destruction zone.