A parting blade having a flat, elongate body, which is delimited by two opposite side surfaces and has two opposite longitudinal edges which are mutually parallel and present chamfered surfaces for wedging the body in a holder, and which includes at least one insert seat formed adjacent to an end, the position of which seat in relation to a longitudinal edge determines the tip height of a turning insert mounted in the insert seat. An attachment part is formed on one of the side surfaces of the blade body. The attachment part is shorter and thinner than the proper blade body and has two opposite longitudinal edges which are mutually parallel and present chamfered surfaces for wedging the attachment part in another holder. In this way, the parting blade can be formed for robust, wide turning inserts and in spite of this be mounted in holders intended for considerably thinner parting blades.
