Summary In the previous paper, Ref. (1) the generation and growth rate of chatter vibration were qualitatively analysed and the parameter of (Wear stiffness)/(Contact stiffness) 2 of grinding wheel was proposed as a principal parameter determining the amplitude growth rate. It is recognised that the wear stiffness and the contact stiffness of grinding wheel vary in a complex manner in the grinding process, and that it is important to know how to identify these two parameters for monitoring the processes. In the present paper, in addition to the concept of estimated contact stiffness, the effective wear stiffness of grinding wheel is introduced, and the variation of these parameters during grinding are analysed experimentally for four different kinds of grinding wheel. The amplitude growth rates of chatter vibration are sequentially estimated using these two parameters and improved estimation accuracy is achieved.