Abstract: An earth-boring bit or head of the shaft or tunnel boring variety has a generally circular bit body. A plurality of saddle members are secured to bit body to receive and support each end of a plurality of corresponding journal members. A cutter shell or sleeve is mounted for rotation on bearings on each journal member. At least one kerf ring is releasably secured to the cutter shell. The kerf ring includes a pair of opposing sides that converge to define a continuous crest for disintegration of formation material. A plurality of hard metal inserts are embedded and secured in rows to the kerf ring, the inserts being generally flush with the sides and extending to the crest of the kerf ring.