This paper deals with the nonlinear models of regenerative chatter on machi
ne tools. The limitations and actual problems of the existing theory are su
mmarized. These cause difficulties in industrial applications, like in the
design of optimum technological parameters, adaptive control and/or vibrati
on-suppression strategies. An industrial machine-tool vibration case is ana
lysed experimentally and conclusions are drawn with respect to the likely m
echanism of the nonlinear behaviour in a four-dimensional phase-space repre
sentation embedded in the infinite-dimensional phase space of regenerative
chatter. In some respects, the whole phenomenon seems to be analogous to th
e turbulence in fluid mechanics.