Drill bit for stone drilling machine - has on the front face surface hardened grooves between hard metal cutting inserts

摘要

Drill bit for a stone drilling machine includes a front side enclosing a number of surfaces projecting in different directions and formed by hard metal inserts. The front surface of the bit body is provided with surface hardened grooves (18) which are positioned between the hard metal inserts (16). The grooves (18) which are projecting through centre line of the bit body are positioned at right angles to each other and are inclined to a plane parallel with longitudinal axis of the bit body. The grooves (18) have a semi-circular section which is constant over their whole length. The front side of the bit body is provided with additional grooves which are positioned each side of the radially projecting hard metal inserts (16). The hard metal inserts (16) are tapering in a cutting edge which is interrupted by spaced recesses (17).