Stone cutting head with three radial cutting inserts - has hard metal plate shaped inserts with convex cutting faces

摘要

The boring head for cutting through stone for borehole drilling, has a set of three hard metal cutting inserts (3) mounted on the tip. Each insert is a plate extending radially outwards from the centre, mounted on a backing block. The blocks are undercut and spaced from each other to leave gaps for distribution of fluid through the hollow centre. Each plate has a convexly curved cutting face (5) and is thicker at the outer end than at the inner end. The curve is tangential to the central axis. The cutting face also slopes back slightly from the vertical central axis seen in side elevation.