Reaming tool as well as a head and a cutting insert therefor

A reaming insert for a reaming tool including a driving rod, a head that has a rotationally symmetrical basic shape and is equipped with one or more detachable cutting inserts, and a clamping member, wherein the head comprises front and rear end surfaces, an envelope surface concentric with a centre axis (C), and a seat that is countersunk in the envelope surface and includes three support surfaces, viz. a radial support surface, a tangential support surface and an axial support surface, wherein the cutting insert has the shape of a mirror-symmetrical polyhedron that comprises six limiting surfaces, two opposite and mutually parallel ones of which are equidistantly separated from a central symmetry plane (SP1) and form chip surfaces that connect to limiting surfaces serving as clearance surfaces via alternately usable, identical cutting edges, wherein the clamping member holds the cutting insert fixed in the seat, and wherein, in at least one of the limiting surfaces of the cutting insert, there is formed a female- or male-like securing means that co-operates with a complementary, male- or female-like securing means in the seat, more precisely in an inactive, contactless state as long as the cutting insert is held pressed against the axial support surface of the seat, the securing means being potentially activatable by being brought into contact with each other in case the cutting insert would unintentionally be distanced from the axial support surface against the action of the clamping member, the reaming insert comprising:

• a female- or male-like securing means,
• wherein the reaming insert has the shape of a mirror-symmetrical polyhedron that comprises six limiting surfaces, two opposite and mutually parallel ones of which are equidistantly separated from a central symmetry plane (SP1) and form chip surfaces that connect to limiting surfaces serving as clearance surfaces via alternately usable, identical cutting edges, and
• wherein the female- or male-like securing means is formed in at least one of the limiting surfaces and has the latent purpose of—in co-operation with a complementary male- or female-like securing means in a seat receiving the cutting insert—counteracting unintentional displacement of the cutting insert in the seat.