Flax harvesting consists of serial technological processes: pulling, separation of seed bolls from stalks, stalks spreading out, turning during a rest, picking up of them and baling in large packages, loading, and transportation. One of the most important operations is seed balls separation from stalks. Determination of parameter of intensity of flex balls combing by deseeder operation is a little studied. Parameter of intensity of a separation doesn't show clearly its dependence on design features and an operating mode of the unit. The authors considered this relation by the example of the comb deseeder which has different tines on a ridge with accidentally decreasing spacing towards the end. The existing deseeders do not provide qualitative combings of flax stalks. Therefore, theoretical and pilot researches of the ridge comb deseeder were conducted. The program and a technique of researches of the comb deseeder were developed. The theoretical basics of intensity of combing by the comb deseeder are covered. The various factors influence damageability of stalks: geometrical parameters of tines, number of at the same time operating combs, sequence of combing, ratio of tines speeds and gripping conveyor. Characteristics of a combed layer, a flax maturing level, the weight-average values of efficiency of single influence belong to the factors influencing intensity of combing. In the flax harvesters LK-4A and LKV-4A with increase in frequency of the comb deseeder to 2.87 rpm and speeds of the gripping conveyor from 1.54 to 1.58 meter per second the intensity decreased up to 3.02 tine per centimeter, and combing purity increased up to 98 percent. So, intensity 3.02 tine per centimeter should be considered as minimum admissible, and combing purity should be increased no more than by 2 percent.