The research discusses the behave of magnetic-abrasive tool (MAT) and the nature of the change of forces mainly of frictional origin which arise in magnetic-abrasive machining (MAM) of cylindric samples with diameter 16 mm, fero-, para- and diamagnetic materials, and circular-form working zone (width 35 mm) in dependence of rotational speed around the working zone axis (range 100–300 rpm), and rotation around the sample axis (range 0–80 rad/sec), with magnetic induction 0,18 and 0,25 T, different types and sizes of magnetic-abrasive powders. The research demonstrated that amount of effective friction torque variates between 0 and 1,4 Nm. Three areas of technological conditions of MAM have been identified: 1) area with quasi-stable magnetic-abrasive tool; 2) area with stable MAT; 3) area with abnormal growing / dropping of friction force. Analysis of obtained patterns has allowed to identify the processes which are associated with the behaving of MAT particles which directly in contact with working surface during MAM. Also, it has allowed to identify the forming conditions of jamming zones which have been placed between magnetic poles and detail surface. It is demonstrated that powders with rounded-form particles create mostly plastic deformation in the surface layer of para- and diamagnetic materials during MAM in these conditions. The greatest impact on the change of friction origin forces creates increasing in magnetic-abrasive powder. The impact of magnetic field forces in these circumstances is insignificant.