A recent development in cutting tool materials for turning hard steels is very high purity cubic Boron Nitride (cBN) without any binder. The performance of this material in interrupted hard turning is studied experimentally in this work. Two new parameters, interruption ratio (IR) and interruptions per unit length (IL) have been defined to characterize cutting interruptions. Turning experiments on 52100 bearing steel (58 HRC), are conducted to study the effect of interruptions on tool life and surface integrity (white layer formation). IL is seen to affect the flank wear in both binderless cBN and in the high cBN tool material. The binderless cBN performed better than the high-cBN tool only for the case where IR is low and IL is high. The flank wear in both tool materials is characterized by groove formation indicating likelihood of three-body type abrasive wear mechanism. While offering no noticeable advantage at low cutting speeds, the binderless cBN's performance at higher speeds does not seem to deteriorate as much as the high cBN tool. Also, the binderless cBN tool is seen to produce thinner white layer than the high cBN tool.