The complexity of studying self-oscillations in the cutting process lies in the simultaneous action of two main excitation sources: coordinate coupling and regeneration of surface waviness during cutting. To address this issue, special oscillator-type cutting tools with single and two degrees of freedom have been developed. The use of single-degree-of-freedom oscillating tools allows the elimination of coordinate coupling influence and enables the study of self-oscillations excitation along individual coordinate axes (X or Z). The design and application of a two-degree-of-freedom oscillating tool with equal stiffness in all directions allow for the study of coupled vibrations regardless of the orientation of the stiffness axes relative to the cutting coordinate system. The scientific novelty lies in isolating and separately analyzing the regenerative mechanism. The practical value lies in more accurately determining the conditions for self-oscillation occurrence, which helps improve cutting process stability, surface quality, and tool life. The aim of this work is to investigate the mechanisms of self-oscillations during turning, taking into account these two key sources. In real cutting conditions, they act simultaneously, making it difficult to analyze their individual contributions to vibration onset.